diff --git a/chrome/browser/net/network_context_configuration_browsertest.cc b/chrome/browser/net/network_context_configuration_browsertest.cc
index b350fb5aed2730..4a8ef21841132b 100644
--- a/chrome/browser/net/network_context_configuration_browsertest.cc
+++ b/chrome/browser/net/network_context_configuration_browsertest.cc
@@ -266,7 +266,7 @@ IN_PROC_BROWSER_TEST_P(NetworkContextConfigurationBrowserTest, PRE_DiskCache) {
   // Make a request whose response should be cached.
   content::ResourceRequest request;
   request.url = test_url;
-  request.headers = "foo: foopity foo\r\n\r\n";
+  request.headers.SetHeader("foo", "foopity foo");
   simple_loader->DownloadToStringOfUnboundedSizeUntilCrashAndDie(
       request, loader_factory(), TRAFFIC_ANNOTATION_FOR_TESTS,
       simple_loader_helper.GetCallback());
diff --git a/components/safe_browsing/DEPS b/components/safe_browsing/DEPS
index aa87f2cc685e4f..227ca28a016462 100644
--- a/components/safe_browsing/DEPS
+++ b/components/safe_browsing/DEPS
@@ -8,6 +8,7 @@ include_rules = [
   "+google_apis",
   "+mojo/public/cpp",
   "+net/base",
+  "+net/http",
   "+net/log",
   "+net/traffic_annotation",
   "+net/url_request",
diff --git a/components/safe_browsing/browser/base_parallel_resource_throttle.cc b/components/safe_browsing/browser/base_parallel_resource_throttle.cc
index a59be63c9a32cf..58399344ad158a 100644
--- a/components/safe_browsing/browser/base_parallel_resource_throttle.cc
+++ b/components/safe_browsing/browser/base_parallel_resource_throttle.cc
@@ -48,8 +48,8 @@ void BaseParallelResourceThrottle::WillStartRequest(bool* defer) {
 
   net::HttpRequestHeaders full_headers;
   resource_request.headers = request_->GetFullRequestHeaders(&full_headers)
-                                 ? full_headers.ToString()
-                                 : request_->extra_request_headers().ToString();
+                                 ? full_headers
+                                 : request_->extra_request_headers();
 
   resource_request.load_flags = request_->load_flags();
   resource_request.resource_type = resource_type_;
diff --git a/components/safe_browsing/browser/mojo_safe_browsing_impl.cc b/components/safe_browsing/browser/mojo_safe_browsing_impl.cc
index c613b93a191c14..c4131c600764dd 100644
--- a/components/safe_browsing/browser/mojo_safe_browsing_impl.cc
+++ b/components/safe_browsing/browser/mojo_safe_browsing_impl.cc
@@ -83,7 +83,7 @@ void MojoSafeBrowsingImpl::CreateCheckerAndCheck(
     mojom::SafeBrowsingUrlCheckerRequest request,
     const GURL& url,
     const std::string& method,
-    const std::string& headers,
+    const net::HttpRequestHeaders& headers,
     int32_t load_flags,
     content::ResourceType resource_type,
     bool has_user_gesture,
diff --git a/components/safe_browsing/browser/mojo_safe_browsing_impl.h b/components/safe_browsing/browser/mojo_safe_browsing_impl.h
index 8e423f5ffd7f26..62b6f9b949f7a4 100644
--- a/components/safe_browsing/browser/mojo_safe_browsing_impl.h
+++ b/components/safe_browsing/browser/mojo_safe_browsing_impl.h
@@ -33,7 +33,7 @@ class MojoSafeBrowsingImpl : public mojom::SafeBrowsing {
                              mojom::SafeBrowsingUrlCheckerRequest request,
                              const GURL& url,
                              const std::string& method,
-                             const std::string& headers,
+                             const net::HttpRequestHeaders& headers,
                              int32_t load_flags,
                              content::ResourceType resource_type,
                              bool has_user_gesture,
diff --git a/components/safe_browsing/browser/safe_browsing_url_checker_impl.cc b/components/safe_browsing/browser/safe_browsing_url_checker_impl.cc
index 35387807cd9c2a..38fce0adfeca1b 100644
--- a/components/safe_browsing/browser/safe_browsing_url_checker_impl.cc
+++ b/components/safe_browsing/browser/safe_browsing_url_checker_impl.cc
@@ -37,7 +37,7 @@ SafeBrowsingUrlCheckerImpl::UrlInfo::UrlInfo(UrlInfo&& other) = default;
 SafeBrowsingUrlCheckerImpl::UrlInfo::~UrlInfo() = default;
 
 SafeBrowsingUrlCheckerImpl::SafeBrowsingUrlCheckerImpl(
-    const std::string& headers,
+    const net::HttpRequestHeaders& headers,
     int load_flags,
     content::ResourceType resource_type,
     bool has_user_gesture,
@@ -142,12 +142,9 @@ void SafeBrowsingUrlCheckerImpl::OnCheckBrowseUrlResult(
   resource.web_contents_getter = web_contents_getter_;
   resource.threat_source = database_manager_->GetThreatSource();
 
-  net::HttpRequestHeaders headers;
-  headers.AddHeadersFromString(headers_);
-
   state_ = STATE_DISPLAYING_BLOCKING_PAGE;
   url_checker_delegate_->StartDisplayingBlockingPageHelper(
-      resource, urls_[next_index_].method, headers,
+      resource, urls_[next_index_].method, headers_,
       resource_type_ == content::RESOURCE_TYPE_MAIN_FRAME, has_user_gesture_);
 }
 
diff --git a/components/safe_browsing/browser/safe_browsing_url_checker_impl.h b/components/safe_browsing/browser/safe_browsing_url_checker_impl.h
index 83328e6980eaf9..d46949feafd01e 100644
--- a/components/safe_browsing/browser/safe_browsing_url_checker_impl.h
+++ b/components/safe_browsing/browser/safe_browsing_url_checker_impl.h
@@ -14,6 +14,7 @@
 #include "components/safe_browsing/common/safe_browsing.mojom.h"
 #include "components/safe_browsing_db/database_manager.h"
 #include "content/public/common/resource_type.h"
+#include "net/http/http_request_headers.h"
 #include "url/gurl.h"
 
 namespace content {
@@ -34,7 +35,7 @@ class SafeBrowsingUrlCheckerImpl : public mojom::SafeBrowsingUrlChecker,
                                    public SafeBrowsingDatabaseManager::Client {
  public:
   SafeBrowsingUrlCheckerImpl(
-      const std::string& headers,
+      const net::HttpRequestHeaders& headers,
       int load_flags,
       content::ResourceType resource_type,
       bool has_user_gesture,
@@ -102,7 +103,7 @@ class SafeBrowsingUrlCheckerImpl : public mojom::SafeBrowsingUrlChecker,
     CheckUrlCallback callback;
   };
 
-  const std::string headers_;
+  const net::HttpRequestHeaders headers_;
   const int load_flags_;
   const content::ResourceType resource_type_;
   const bool has_user_gesture_;
diff --git a/components/safe_browsing/common/BUILD.gn b/components/safe_browsing/common/BUILD.gn
index 6de5638d5bcfcc..7fc71ce008e590 100644
--- a/components/safe_browsing/common/BUILD.gn
+++ b/components/safe_browsing/common/BUILD.gn
@@ -63,6 +63,7 @@ mojom("interfaces") {
 
   public_deps = [
     "//content/public/common:resource_type_bindings",
+    "//services/network/public/interfaces",
     "//url/mojo:url_mojom_gurl",
   ]
 }
diff --git a/components/safe_browsing/common/safe_browsing.mojom b/components/safe_browsing/common/safe_browsing.mojom
index ee79cb2e9c86c1..fc1a84257637cd 100644
--- a/components/safe_browsing/common/safe_browsing.mojom
+++ b/components/safe_browsing/common/safe_browsing.mojom
@@ -5,6 +5,7 @@
 module safe_browsing.mojom;
 
 import "content/public/common/resource_type.mojom";
+import "services/network/public/interfaces/http_request_headers.mojom";
 import "url/mojo/url.mojom";
 
 // Provided by the browser and used by renderers to perform SafeBrowsing URL
@@ -32,7 +33,7 @@ interface SafeBrowsing {
       SafeBrowsingUrlChecker& request,
       url.mojom.Url url,
       string method,
-      string headers,
+      network.mojom.HttpRequestHeaders headers,
       int32 load_flags,
       content.mojom.ResourceType resource_type,
       bool has_user_gesture) => (bool proceed, bool showed_interstitial);
diff --git a/components/safe_browsing/renderer/renderer_url_loader_throttle.cc b/components/safe_browsing/renderer/renderer_url_loader_throttle.cc
index 32af062814b798..5f299b0ba2c04c 100644
--- a/components/safe_browsing/renderer/renderer_url_loader_throttle.cc
+++ b/components/safe_browsing/renderer/renderer_url_loader_throttle.cc
@@ -31,10 +31,12 @@ void RendererURLLoaderThrottle::WillStartRequest(
   pending_checks_++;
   // Use a weak pointer to self because |safe_browsing_| is not owned by this
   // object.
+  net::HttpRequestHeaders headers;
+  headers.CopyFrom(request.headers);
   safe_browsing_->CreateCheckerAndCheck(
       render_frame_id_, mojo::MakeRequest(&url_checker_), request.url,
-      request.method, request.headers, request.load_flags,
-      request.resource_type, request.has_user_gesture,
+      request.method, headers, request.load_flags, request.resource_type,
+      request.has_user_gesture,
       base::BindOnce(&RendererURLLoaderThrottle::OnCheckUrlResult,
                      weak_factory_.GetWeakPtr()));
   safe_browsing_ = nullptr;
diff --git a/components/safe_browsing/renderer/websocket_sb_handshake_throttle.cc b/components/safe_browsing/renderer/websocket_sb_handshake_throttle.cc
index 5eb84dcc189b88..78863359f57972 100644
--- a/components/safe_browsing/renderer/websocket_sb_handshake_throttle.cc
+++ b/components/safe_browsing/renderer/websocket_sb_handshake_throttle.cc
@@ -15,6 +15,7 @@
 #include "content/public/renderer/render_frame.h"
 #include "ipc/ipc_message.h"
 #include "mojo/public/cpp/bindings/interface_request.h"
+#include "net/http/http_request_headers.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 #include "third_party/WebKit/public/platform/WebURL.h"
 
@@ -60,7 +61,8 @@ void WebSocketSBHandshakeThrottle::ThrottleHandshake(
   start_time_ = base::TimeTicks::Now();
   safe_browsing_->CreateCheckerAndCheck(
       render_frame_id, mojo::MakeRequest(&url_checker_), url, "GET",
-      std::string(), load_flags, content::RESOURCE_TYPE_SUB_RESOURCE, false,
+      net::HttpRequestHeaders(), load_flags,
+      content::RESOURCE_TYPE_SUB_RESOURCE, false,
       base::BindOnce(&WebSocketSBHandshakeThrottle::OnCheckResult,
                      weak_factory_.GetWeakPtr()));
 
diff --git a/components/safe_browsing/renderer/websocket_sb_handshake_throttle_unittest.cc b/components/safe_browsing/renderer/websocket_sb_handshake_throttle_unittest.cc
index 6a760bb8efed62..d011d27247ac12 100644
--- a/components/safe_browsing/renderer/websocket_sb_handshake_throttle_unittest.cc
+++ b/components/safe_browsing/renderer/websocket_sb_handshake_throttle_unittest.cc
@@ -14,6 +14,7 @@
 #include "content/public/common/resource_type.h"
 #include "ipc/ipc_message.h"
 #include "mojo/public/cpp/bindings/binding.h"
+#include "net/http/http_request_headers.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/platform/WebString.h"
@@ -37,7 +38,7 @@ class FakeSafeBrowsing : public mojom::SafeBrowsing {
                              mojom::SafeBrowsingUrlCheckerRequest request,
                              const GURL& url,
                              const std::string& method,
-                             const std::string& headers,
+                             const net::HttpRequestHeaders& headers,
                              int32_t load_flags,
                              content::ResourceType resource_type,
                              bool has_user_gesture,
@@ -60,7 +61,7 @@ class FakeSafeBrowsing : public mojom::SafeBrowsing {
   mojom::SafeBrowsingUrlCheckerRequest request_;
   GURL url_;
   std::string method_;
-  std::string headers_;
+  net::HttpRequestHeaders headers_;
   int32_t load_flags_;
   content::ResourceType resource_type_;
   bool has_user_gesture_;
@@ -119,7 +120,7 @@ TEST_F(WebSocketSBHandshakeThrottleTest, CheckArguments) {
   EXPECT_EQ(MSG_ROUTING_NONE, safe_browsing_.render_frame_id_);
   EXPECT_EQ(GURL(kTestUrl), safe_browsing_.url_);
   EXPECT_EQ("GET", safe_browsing_.method_);
-  EXPECT_TRUE(safe_browsing_.headers_.empty());
+  EXPECT_TRUE(safe_browsing_.headers_.GetHeaderVector().empty());
   EXPECT_EQ(0, safe_browsing_.load_flags_);
   EXPECT_EQ(content::RESOURCE_TYPE_SUB_RESOURCE, safe_browsing_.resource_type_);
   EXPECT_FALSE(safe_browsing_.has_user_gesture_);
diff --git a/content/browser/appcache/appcache_update_job_unittest.cc b/content/browser/appcache/appcache_update_job_unittest.cc
index d91219f363d0fc..05d1c39df9edcf 100644
--- a/content/browser/appcache/appcache_update_job_unittest.cc
+++ b/content/browser/appcache/appcache_update_job_unittest.cc
@@ -608,9 +608,7 @@ class MockURLLoaderFactory : public mojom::URLLoaderFactory {
       return;
     }
 
-    net::HttpRequestHeaders request_headers;
-    request_headers.AddHeadersFromString(url_request.headers);
-    HttpHeadersRequestTestJob::ValidateExtraHeaders(request_headers);
+    HttpHeadersRequestTestJob::ValidateExtraHeaders(url_request.headers);
 
     std::string headers;
     std::string body;
diff --git a/content/browser/appcache/appcache_update_url_loader_request.cc b/content/browser/appcache/appcache_update_url_loader_request.cc
index c6171c38a1f1f9..ae46c3ca297019 100644
--- a/content/browser/appcache/appcache_update_url_loader_request.cc
+++ b/content/browser/appcache/appcache_update_url_loader_request.cc
@@ -30,7 +30,7 @@ void AppCacheUpdateJob::UpdateURLLoaderRequest::Start() {
 
 void AppCacheUpdateJob::UpdateURLLoaderRequest::SetExtraRequestHeaders(
     const net::HttpRequestHeaders& headers) {
-  request_.headers = headers.ToString();
+  request_.headers = headers;
 }
 
 GURL AppCacheUpdateJob::UpdateURLLoaderRequest::GetURL() const {
diff --git a/content/browser/appcache/appcache_url_loader_job.cc b/content/browser/appcache/appcache_url_loader_job.cc
index 74591da9b3952d..0dddb4be63043e 100644
--- a/content/browser/appcache/appcache_url_loader_job.cc
+++ b/content/browser/appcache/appcache_url_loader_job.cc
@@ -59,9 +59,7 @@ void AppCacheURLLoaderJob::DeliverAppCachedResponse(const GURL& manifest_url,
   is_fallback_ = is_fallback;
 
   // Handle range requests.
-  net::HttpRequestHeaders headers;
-  headers.AddHeadersFromString(request_.headers);
-  InitializeRangeRequestInfo(headers);
+  InitializeRangeRequestInfo(request_.headers);
 
   // TODO(ananta)
   // Implement the AppCacheServiceImpl::Observer interface or add weak pointer
diff --git a/content/browser/blob_storage/blob_url_loader_factory.cc b/content/browser/blob_storage/blob_url_loader_factory.cc
index e4d165545c3b19..a783374b447457 100644
--- a/content/browser/blob_storage/blob_url_loader_factory.cc
+++ b/content/browser/blob_storage/blob_url_loader_factory.cc
@@ -76,10 +76,8 @@ class BlobURLLoader : public storage::MojoBlobReader::Delegate,
       return;
     }
 
-    net::HttpRequestHeaders request_headers;
-    request_headers.AddHeadersFromString(request.headers);
     std::string range_header;
-    if (request_headers.GetHeader(net::HttpRequestHeaders::kRange,
+    if (request.headers.GetHeader(net::HttpRequestHeaders::kRange,
                                   &range_header)) {
       // We only care about "Range" header here.
       std::vector<net::HttpByteRange> ranges;
diff --git a/content/browser/blob_storage/blob_url_unittest.cc b/content/browser/blob_storage/blob_url_unittest.cc
index da49844e97d06d..dbfa815e6b80b2 100644
--- a/content/browser/blob_storage/blob_url_unittest.cc
+++ b/content/browser/blob_storage/blob_url_unittest.cc
@@ -277,8 +277,7 @@ class BlobURLRequestJobTest : public testing::TestWithParam<bool> {
       ResourceRequest request;
       request.url = url;
       request.method = method;
-      if (!extra_headers.IsEmpty())
-        request.headers = extra_headers.ToString();
+      request.headers = extra_headers;
 
       mojom::URLLoaderPtr url_loader;
       TestURLLoaderClient url_loader_client;
diff --git a/content/browser/devtools/protocol/network_handler.cc b/content/browser/devtools/protocol/network_handler.cc
index 8b406dc568da7f..a7970f9fec4268 100644
--- a/content/browser/devtools/protocol/network_handler.cc
+++ b/content/browser/devtools/protocol/network_handler.cc
@@ -788,9 +788,7 @@ void NetworkHandler::NavigationPreloadRequestSent(
     return;
   const std::string version_id(base::IntToString(worker_version_id));
   std::unique_ptr<DictionaryValue> headers_dict(DictionaryValue::create());
-  net::HttpRequestHeaders headers;
-  headers.AddHeadersFromString(request.headers);
-  for (net::HttpRequestHeaders::Iterator it(headers); it.GetNext();)
+  for (net::HttpRequestHeaders::Iterator it(request.headers); it.GetNext();)
     headers_dict->setString(it.name(), it.value());
   frontend_->RequestWillBeSent(
       request_id, "" /* loader_id */, request.url.spec(),
diff --git a/content/browser/download/download_utils.cc b/content/browser/download/download_utils.cc
index 319a3fa09f4449..bb824e754bf3fe 100644
--- a/content/browser/download/download_utils.cc
+++ b/content/browser/download/download_utils.cc
@@ -212,8 +212,7 @@ std::unique_ptr<ResourceRequest> CreateResourceRequest(
   // Add additional request headers.
   std::unique_ptr<net::HttpRequestHeaders> headers =
       GetAdditionalRequestHeaders(params);
-  if (!headers->IsEmpty())
-    request->headers = headers->ToString();
+  request->headers.Swap(headers.get());
 
   return request;
 }
diff --git a/content/browser/loader/navigation_url_loader_network_service.cc b/content/browser/loader/navigation_url_loader_network_service.cc
index 8a9139cc0c5323..2c04b2cd13cd6b 100644
--- a/content/browser/loader/navigation_url_loader_network_service.cc
+++ b/content/browser/loader/navigation_url_loader_network_service.cc
@@ -436,7 +436,7 @@ NavigationURLLoaderNetworkService::NavigationURLLoaderNetworkService(
   new_request->request_initiator = request_info->begin_params.initiator_origin;
   new_request->referrer = request_info->common_params.referrer.url;
   new_request->referrer_policy = request_info->common_params.referrer.policy;
-  new_request->headers = request_info->begin_params.headers;
+  new_request->headers.AddHeadersFromString(request_info->begin_params.headers);
 
   int load_flags = request_info->begin_params.load_flags;
   load_flags |= net::LOAD_VERIFY_EV_CERT;
diff --git a/content/browser/loader/resource_dispatcher_host_impl.cc b/content/browser/loader/resource_dispatcher_host_impl.cc
index a3ae030d861dd0..8014945301d5ff 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.cc
+++ b/content/browser/loader/resource_dispatcher_host_impl.cc
@@ -1166,12 +1166,9 @@ void ResourceDispatcherHostImpl::BeginRequest(
 
   // Parse the headers before calling ShouldServiceRequest, so that they are
   // available to be validated.
-  net::HttpRequestHeaders headers;
-  headers.AddHeadersFromString(request_data.headers);
-
   if (is_shutdown_ ||
-      !ShouldServiceRequest(child_id, request_data, headers, requester_info,
-                            resource_context)) {
+      !ShouldServiceRequest(child_id, request_data, request_data.headers,
+                            requester_info, resource_context)) {
     AbortRequestBeforeItStarts(requester_info->filter(), sync_result_handler,
                                request_id, std::move(url_loader_client));
     return;
@@ -1204,7 +1201,8 @@ void ResourceDispatcherHostImpl::BeginRequest(
     // yes then we need to mark the current request as pending and wait for the
     // interceptor to invoke the callback with a status code indicating whether
     // the request needs to be aborted or continued.
-    for (net::HttpRequestHeaders::Iterator it(headers); it.GetNext();) {
+    for (net::HttpRequestHeaders::Iterator it(request_data.headers);
+         it.GetNext();) {
       HeaderInterceptorMap::iterator index =
           http_header_interceptor_map_.find(it.name());
       if (index != http_header_interceptor_map_.end()) {
@@ -1223,7 +1221,8 @@ void ResourceDispatcherHostImpl::BeginRequest(
                   &ResourceDispatcherHostImpl::ContinuePendingBeginRequest,
                   base::Unretained(this), make_scoped_refptr(requester_info),
                   request_id, request_data, is_sync_load, sync_result_handler,
-                  route_id, headers, base::Passed(std::move(mojo_request)),
+                  route_id, request_data.headers,
+                  base::Passed(std::move(mojo_request)),
                   base::Passed(std::move(url_loader_client)),
                   base::Passed(std::move(blob_handles)), traffic_annotation));
           return;
@@ -1231,11 +1230,12 @@ void ResourceDispatcherHostImpl::BeginRequest(
       }
     }
   }
-  ContinuePendingBeginRequest(
-      requester_info, request_id, request_data, is_sync_load,
-      sync_result_handler, route_id, headers, std::move(mojo_request),
-      std::move(url_loader_client), std::move(blob_handles), traffic_annotation,
-      HeaderInterceptorResult::CONTINUE);
+  ContinuePendingBeginRequest(requester_info, request_id, request_data,
+                              is_sync_load, sync_result_handler, route_id,
+                              request_data.headers, std::move(mojo_request),
+                              std::move(url_loader_client),
+                              std::move(blob_handles), traffic_annotation,
+                              HeaderInterceptorResult::CONTINUE);
 }
 
 void ResourceDispatcherHostImpl::ContinuePendingBeginRequest(
diff --git a/content/browser/security_exploit_browsertest.cc b/content/browser/security_exploit_browsertest.cc
index 241fcb550ffd48..95023029e755aa 100644
--- a/content/browser/security_exploit_browsertest.cc
+++ b/content/browser/security_exploit_browsertest.cc
@@ -139,7 +139,7 @@ ResourceRequest CreateXHRRequest(const char* url) {
 ResourceRequest CreateXHRRequestWithOrigin(const char* origin) {
   ResourceRequest request = CreateXHRRequest("http://bar.com/simple_page.html");
   request.site_for_cookies = GURL(origin);
-  request.headers = base::StringPrintf("Origin: %s\r\n", origin);
+  request.headers.SetHeader(net::HttpRequestHeaders::kOrigin, origin);
   return request;
 }
 
diff --git a/content/browser/service_worker/service_worker_controllee_request_handler.cc b/content/browser/service_worker/service_worker_controllee_request_handler.cc
index 19acfff5e20961..8be993b349657e 100644
--- a/content/browser/service_worker/service_worker_controllee_request_handler.cc
+++ b/content/browser/service_worker/service_worker_controllee_request_handler.cc
@@ -213,9 +213,7 @@ void ServiceWorkerControlleeRequestHandler::MaybeCreateLoader(
 #if BUILDFLAG(ENABLE_OFFLINE_PAGES)
   // Fall back for the subsequent offline page interceptor to load the offline
   // snapshot of the page if required.
-  net::HttpRequestHeaders extra_request_headers;
-  extra_request_headers.AddHeadersFromString(resource_request.headers);
-  if (ShouldFallbackToLoadOfflinePage(extra_request_headers)) {
+  if (ShouldFallbackToLoadOfflinePage(resource_request.headers)) {
     std::move(callback).Run(StartLoaderCallback());
     return;
   }
diff --git a/content/browser/service_worker/service_worker_fetch_dispatcher.cc b/content/browser/service_worker/service_worker_fetch_dispatcher.cc
index 4e01ed4df0a20d..d4ffc47b385579 100644
--- a/content/browser/service_worker/service_worker_fetch_dispatcher.cc
+++ b/content/browser/service_worker/service_worker_fetch_dispatcher.cc
@@ -654,9 +654,9 @@ bool ServiceWorkerFetchDispatcher::MaybeStartNavigationPreload(
       version_->navigation_preload_state().header));
   ServiceWorkerMetrics::RecordNavigationPreloadRequestHeaderSize(
       version_->navigation_preload_state().header.length());
-  request.headers = "Service-Worker-Navigation-Preload: " +
-                    version_->navigation_preload_state().header + "\r\n" +
-                    original_request->extra_request_headers().ToString();
+  request.headers.CopyFrom(original_request->extra_request_headers());
+  request.headers.SetHeader("Service-Worker-Navigation-Preload",
+                            version_->navigation_preload_state().header);
 
   const int request_id = ResourceDispatcherHostImpl::Get()->MakeRequestID();
   DCHECK_LT(request_id, -1);
diff --git a/content/browser/webui/web_ui_url_loader_factory.cc b/content/browser/webui/web_ui_url_loader_factory.cc
index 3c49b85b04747f..82382f3806d159 100644
--- a/content/browser/webui/web_ui_url_loader_factory.cc
+++ b/content/browser/webui/web_ui_url_loader_factory.cc
@@ -156,10 +156,8 @@ void StartURLLoader(const ResourceRequest& request,
   std::string path;
   URLDataManagerBackend::URLToRequestPath(request.url, &path);
 
-  net::HttpRequestHeaders request_headers;
-  request_headers.AddHeadersFromString(request.headers);
   std::string origin_header;
-  request_headers.GetHeader(net::HttpRequestHeaders::kOrigin, &origin_header);
+  request.headers.GetHeader(net::HttpRequestHeaders::kOrigin, &origin_header);
 
   scoped_refptr<net::HttpResponseHeaders> headers =
       URLDataManagerBackend::GetHeaders(source, path, origin_header);
diff --git a/content/child/web_url_request_util.cc b/content/child/web_url_request_util.cc
index ce7efdab59b503..1081d7c137147e 100644
--- a/content/child/web_url_request_util.cc
+++ b/content/child/web_url_request_util.cc
@@ -14,6 +14,7 @@
 #include "content/child/request_extra_data.h"
 #include "net/base/load_flags.h"
 #include "net/base/net_errors.h"
+#include "net/http/http_util.h"
 #include "third_party/WebKit/public/platform/FilePathConversion.h"
 #include "third_party/WebKit/public/platform/WebCachePolicy.h"
 #include "third_party/WebKit/public/platform/WebData.h"
@@ -31,6 +32,39 @@ namespace content {
 
 namespace {
 
+std::string TrimLWSAndCRLF(const base::StringPiece& input) {
+  base::StringPiece string = net::HttpUtil::TrimLWS(input);
+  const char* begin = string.data();
+  const char* end = string.data() + string.size();
+  while (begin < end && (end[-1] == '\r' || end[-1] == '\n'))
+    --end;
+  return std::string(base::StringPiece(begin, end - begin));
+}
+
+class HttpRequestHeadersVisitor : public blink::WebHTTPHeaderVisitor {
+ public:
+  explicit HttpRequestHeadersVisitor(net::HttpRequestHeaders* headers)
+      : headers_(headers) {}
+  ~HttpRequestHeadersVisitor() override = default;
+
+  void VisitHeader(const WebString& name, const WebString& value) override {
+    std::string name_latin1 = name.Latin1();
+    std::string value_latin1 = TrimLWSAndCRLF(value.Latin1());
+
+    // Skip over referrer headers found in the header map because we already
+    // pulled it out as a separate parameter.
+    if (base::LowerCaseEqualsASCII(name_latin1, "referer"))
+      return;
+
+    DCHECK(net::HttpUtil::IsValidHeaderName(name_latin1)) << name_latin1;
+    DCHECK(net::HttpUtil::IsValidHeaderValue(value_latin1)) << value_latin1;
+    headers_->SetHeader(name_latin1, value_latin1);
+  }
+
+ private:
+  net::HttpRequestHeaders* const headers_;
+};
+
 class HeaderFlattener : public blink::WebHTTPHeaderVisitor {
  public:
   HeaderFlattener() {}
@@ -180,7 +214,16 @@ ResourceType WebURLRequestToResourceType(const WebURLRequest& request) {
   return WebURLRequestContextToResourceType(request_context);
 }
 
-std::string GetWebURLRequestHeaders(const WebURLRequest& request) {
+net::HttpRequestHeaders GetWebURLRequestHeaders(
+    const blink::WebURLRequest& request) {
+  net::HttpRequestHeaders headers;
+  HttpRequestHeadersVisitor visitor(&headers);
+  request.VisitHTTPHeaderFields(&visitor);
+  return headers;
+}
+
+std::string GetWebURLRequestHeadersAsString(
+    const blink::WebURLRequest& request) {
   HeaderFlattener flattener;
   request.VisitHTTPHeaderFields(&flattener);
   return flattener.GetBuffer();
diff --git a/content/child/web_url_request_util.h b/content/child/web_url_request_util.h
index 77c92cc86881fe..f7f8a8839f53b5 100644
--- a/content/child/web_url_request_util.h
+++ b/content/child/web_url_request_util.h
@@ -13,6 +13,7 @@
 #include "content/public/common/resource_request_body.h"
 #include "content/public/common/resource_type.h"
 #include "content/public/common/service_worker_modes.h"
+#include "net/http/http_request_headers.h"
 #include "third_party/WebKit/public/platform/WebMixedContentContextType.h"
 #include "third_party/WebKit/public/platform/WebURLRequest.h"
 
@@ -28,7 +29,11 @@ ResourceType WebURLRequestContextToResourceType(
 CONTENT_EXPORT ResourceType WebURLRequestToResourceType(
     const blink::WebURLRequest& request);
 
-std::string GetWebURLRequestHeaders(const blink::WebURLRequest& request);
+net::HttpRequestHeaders GetWebURLRequestHeaders(
+    const blink::WebURLRequest& request);
+
+std::string GetWebURLRequestHeadersAsString(
+    const blink::WebURLRequest& request);
 
 int GetLoadFlagsForWebURLRequest(const blink::WebURLRequest& request);
 
diff --git a/content/network/url_loader_impl.cc b/content/network/url_loader_impl.cc
index 40e38e5616fbd8..c6f6a6cf43b251 100644
--- a/content/network/url_loader_impl.cc
+++ b/content/network/url_loader_impl.cc
@@ -192,9 +192,7 @@ URLLoaderImpl::URLLoaderImpl(
   const Referrer referrer(request.referrer, request.referrer_policy);
   Referrer::SetReferrerForRequest(url_request_.get(), referrer);
 
-  net::HttpRequestHeaders headers;
-  headers.AddHeadersFromString(request.headers);
-  url_request_->SetExtraRequestHeaders(headers);
+  url_request_->SetExtraRequestHeaders(request.headers);
 
   // Resolve elements from request_body and prepare upload data.
   if (request.request_body.get()) {
diff --git a/content/public/common/common_param_traits.cc b/content/public/common/common_param_traits.cc
index 2a990c4c3119f0..281c1c29350016 100644
--- a/content/public/common/common_param_traits.cc
+++ b/content/public/common/common_param_traits.cc
@@ -13,6 +13,8 @@
 #include "net/base/host_port_pair.h"
 #include "net/base/ip_address.h"
 #include "net/base/ip_endpoint.h"
+#include "net/http/http_request_headers.h"
+#include "net/http/http_util.h"
 
 namespace IPC {
 
@@ -94,6 +96,43 @@ void ParamTraits<net::HostPortPair>::Log(const param_type& p, std::string* l) {
   l->append(p.ToString());
 }
 
+void ParamTraits<net::HttpRequestHeaders>::GetSize(base::PickleSizer* s,
+                                                   const param_type& p) {
+  GetParamSize(s, static_cast<int>(p.GetHeaderVector().size()));
+  for (size_t i = 0; i < p.GetHeaderVector().size(); ++i)
+    GetParamSize(s, p.GetHeaderVector()[i]);
+}
+
+void ParamTraits<net::HttpRequestHeaders>::Write(base::Pickle* m,
+                                                 const param_type& p) {
+  WriteParam(m, static_cast<int>(p.GetHeaderVector().size()));
+  for (size_t i = 0; i < p.GetHeaderVector().size(); ++i)
+    WriteParam(m, p.GetHeaderVector()[i]);
+}
+
+bool ParamTraits<net::HttpRequestHeaders>::Read(const base::Pickle* m,
+                                                base::PickleIterator* iter,
+                                                param_type* r) {
+  // Sanity check.
+  int size;
+  if (!iter->ReadLength(&size))
+    return false;
+  for (int i = 0; i < size; ++i) {
+    net::HttpRequestHeaders::HeaderKeyValuePair pair;
+    if (!ReadParam(m, iter, &pair) ||
+        !net::HttpUtil::IsValidHeaderName(pair.key) ||
+        !net::HttpUtil::IsValidHeaderValue(pair.value))
+      return false;
+    r->SetHeader(pair.key, pair.value);
+  }
+  return true;
+}
+
+void ParamTraits<net::HttpRequestHeaders>::Log(const param_type& p,
+                                               std::string* l) {
+  l->append(p.ToString());
+}
+
 void ParamTraits<net::IPEndPoint>::GetSize(base::PickleSizer* s,
                                            const param_type& p) {
   GetParamSize(s, p.address());
diff --git a/content/public/common/common_param_traits.h b/content/public/common/common_param_traits.h
index 86659951f75208..3dcbcea77fc357 100644
--- a/content/public/common/common_param_traits.h
+++ b/content/public/common/common_param_traits.h
@@ -38,6 +38,7 @@ class PageState;
 
 namespace net {
 class HostPortPair;
+class HttpRequestHeaders;
 class IPAddress;
 class IPEndPoint;
 }
@@ -66,6 +67,17 @@ struct CONTENT_EXPORT ParamTraits<net::HostPortPair> {
   static void Log(const param_type& p, std::string* l);
 };
 
+template <>
+struct CONTENT_EXPORT ParamTraits<net::HttpRequestHeaders> {
+  typedef net::HttpRequestHeaders param_type;
+  static void GetSize(base::PickleSizer* s, const param_type& p);
+  static void Write(base::Pickle* m, const param_type& p);
+  static bool Read(const base::Pickle* m,
+                   base::PickleIterator* iter,
+                   param_type* r);
+  static void Log(const param_type& p, std::string* l);
+};
+
 template <>
 struct CONTENT_EXPORT ParamTraits<net::IPEndPoint> {
   typedef net::IPEndPoint param_type;
diff --git a/content/public/common/common_param_traits_macros.h b/content/public/common/common_param_traits_macros.h
index f0df22851a1c51..074c17220e9786 100644
--- a/content/public/common/common_param_traits_macros.h
+++ b/content/public/common/common_param_traits_macros.h
@@ -16,6 +16,7 @@
 #include "ipc/ipc_message_macros.h"
 #include "net/base/network_change_notifier.h"
 #include "net/base/request_priority.h"
+#include "net/http/http_request_headers.h"
 #include "net/nqe/effective_connection_type.h"
 #include "third_party/WebKit/public/platform/WebPoint.h"
 #include "third_party/WebKit/public/platform/WebRect.h"
@@ -290,4 +291,9 @@ IPC_STRUCT_TRAITS_BEGIN(ui::AXRelativeBounds)
   IPC_STRUCT_TRAITS_MEMBER(transform)
 IPC_STRUCT_TRAITS_END()
 
+IPC_STRUCT_TRAITS_BEGIN(net::HttpRequestHeaders::HeaderKeyValuePair)
+  IPC_STRUCT_TRAITS_MEMBER(key)
+  IPC_STRUCT_TRAITS_MEMBER(value)
+IPC_STRUCT_TRAITS_END()
+
 #endif  // CONTENT_PUBLIC_COMMON_COMMON_PARAM_TRAITS_MACROS_H_
diff --git a/content/public/common/resource_request.h b/content/public/common/resource_request.h
index f776dfc97ed2f9..f5fb4e3d47846c 100644
--- a/content/public/common/resource_request.h
+++ b/content/public/common/resource_request.h
@@ -18,6 +18,7 @@
 #include "content/public/common/resource_type.h"
 #include "content/public/common/service_worker_modes.h"
 #include "net/base/request_priority.h"
+#include "net/http/http_request_headers.h"
 #include "third_party/WebKit/public/platform/WebMixedContentContextType.h"
 #include "third_party/WebKit/public/platform/WebPageVisibilityState.h"
 #include "third_party/WebKit/public/platform/WebReferrerPolicy.h"
@@ -61,12 +62,7 @@ struct CONTENT_EXPORT ResourceRequest {
       blink::kWebPageVisibilityStateVisible;
 
   // Additional HTTP request headers.
-  //
-  // For HTTP(S) requests, the headers parameter can be a \r\n-delimited and
-  // \r\n-terminated list of MIME headers.  They should be ASCII-encoded using
-  // the standard MIME header encoding rules.  The headers parameter can also
-  // be null if no extra request headers need to be set.
-  std::string headers;
+  net::HttpRequestHeaders headers;
 
   // net::URLRequest load flags (0 by default).
   int load_flags = 0;
diff --git a/content/public/common/simple_url_loader_unittest.cc b/content/public/common/simple_url_loader_unittest.cc
index 6e43aad46fd291..00460a94277ada 100644
--- a/content/public/common/simple_url_loader_unittest.cc
+++ b/content/public/common/simple_url_loader_unittest.cc
@@ -239,7 +239,7 @@ TEST_F(SimpleURLLoaderTest, BasicRequest) {
   // Use a more interesting request than "/echo", just to verify more than the
   // request URL is hooked up.
   resource_request.url = test_server_.GetURL("/echoheader?foo");
-  resource_request.headers = "foo: Expected Response";
+  resource_request.headers.SetHeader("foo", "Expected Response");
   WaitForStringHelper string_helper;
   string_helper.RunRequest(url_loader_factory_.get(), resource_request);
 
diff --git a/content/renderer/fetchers/resource_fetcher_impl.cc b/content/renderer/fetchers/resource_fetcher_impl.cc
index 9e19b19b2c0bdf..29c1899bb212a0 100644
--- a/content/renderer/fetchers/resource_fetcher_impl.cc
+++ b/content/renderer/fetchers/resource_fetcher_impl.cc
@@ -279,7 +279,7 @@ void ResourceFetcherImpl::SetHeader(const std::string& header,
     DCHECK(request_.referrer.is_valid());
     request_.referrer_policy = blink::kWebReferrerPolicyDefault;
   } else {
-    headers_.SetHeader(header, value);
+    request_.headers.SetHeader(header, value);
   }
 }
 
@@ -344,9 +344,6 @@ void ResourceFetcherImpl::Start(
     SetHeader(kAccessControlAllowOriginHeader,
               blink::WebSecurityOrigin::CreateUnique().ToString().Ascii());
   }
-  if (!headers_.IsEmpty())
-    request_.headers = headers_.ToString();
-
   request_.resource_type = WebURLRequestContextToResourceType(request_context);
 
   client_ = base::MakeUnique<ClientImpl>(this, callback, maximum_download_size);
diff --git a/content/renderer/fetchers/resource_fetcher_impl.h b/content/renderer/fetchers/resource_fetcher_impl.h
index ec91621924260a..74a8cefae29904 100644
--- a/content/renderer/fetchers/resource_fetcher_impl.h
+++ b/content/renderer/fetchers/resource_fetcher_impl.h
@@ -60,11 +60,6 @@ class ResourceFetcherImpl : public ResourceFetcher {
   // Request to send.
   ResourceRequest request_;
 
-  // HTTP headers to build a header string for |request_|.
-  // TODO(toyoshim): Remove this member once ResourceRequest uses
-  // net::HttpRequestHeaders instead of std::string for headers.
-  net::HttpRequestHeaders headers_;
-
   // Limit how long to wait for the server.
   base::OneShotTimer timeout_timer_;
 
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 7fc594620793bf..66e30fc4379b76 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -5983,7 +5983,7 @@ void RenderFrameImpl::OpenURL(const NavigationPolicyInfo& info,
   params.uses_post = IsHttpPost(info.url_request);
   params.resource_request_body =
       GetRequestBodyForWebURLRequest(info.url_request);
-  params.extra_headers = GetWebURLRequestHeaders(info.url_request);
+  params.extra_headers = GetWebURLRequestHeadersAsString(info.url_request);
   params.referrer = send_referrer ? RenderViewImpl::GetReferrerFromRequest(
                                         frame_, info.url_request)
                                   : content::Referrer();
@@ -6469,7 +6469,7 @@ void RenderFrameImpl::BeginNavigation(const NavigationPolicyInfo& info) {
       info.navigation_type == blink::kWebNavigationTypeFormResubmitted;
 
   BeginNavigationParams begin_navigation_params(
-      GetWebURLRequestHeaders(info.url_request), load_flags,
+      GetWebURLRequestHeadersAsString(info.url_request), load_flags,
       info.url_request.HasUserGesture(),
       info.url_request.GetServiceWorkerMode() !=
           blink::WebURLRequest::ServiceWorkerMode::kAll,
diff --git a/content/renderer/render_frame_proxy.cc b/content/renderer/render_frame_proxy.cc
index c754839797661e..fd083b0fa60cbb 100644
--- a/content/renderer/render_frame_proxy.cc
+++ b/content/renderer/render_frame_proxy.cc
@@ -535,7 +535,7 @@ void RenderFrameProxy::Navigate(const blink::WebURLRequest& request,
   params.url = request.Url();
   params.uses_post = request.HttpMethod().Utf8() == "POST";
   params.resource_request_body = GetRequestBodyForWebURLRequest(request);
-  params.extra_headers = GetWebURLRequestHeaders(request);
+  params.extra_headers = GetWebURLRequestHeadersAsString(request);
   params.referrer = Referrer(blink::WebStringToGURL(request.HttpHeaderField(
                                  blink::WebString::FromUTF8("Referer"))),
                              request.GetReferrerPolicy());
diff --git a/mojo/public/tools/bindings/chromium_bindings_configuration.gni b/mojo/public/tools/bindings/chromium_bindings_configuration.gni
index 6fe236dcf45371..976edf30688ab2 100644
--- a/mojo/public/tools/bindings/chromium_bindings_configuration.gni
+++ b/mojo/public/tools/bindings/chromium_bindings_configuration.gni
@@ -30,6 +30,7 @@ _typemap_imports = [
   "//net/interfaces/typemaps.gni",
   "//services/device/public/interfaces/typemaps.gni",
   "//services/identity/public/cpp/typemaps.gni",
+  "//services/network/public/cpp/typemaps.gni",
   "//services/preferences/public/cpp/typemaps.gni",
   "//services/resource_coordinator/public/cpp/typemaps.gni",
   "//services/service_manager/public/cpp/typemaps.gni",
diff --git a/net/http/http_request_headers.cc b/net/http/http_request_headers.cc
index b2fec436b08504..65659b4c219812 100644
--- a/net/http/http_request_headers.cc
+++ b/net/http/http_request_headers.cc
@@ -94,13 +94,9 @@ void HttpRequestHeaders::Clear() {
 
 void HttpRequestHeaders::SetHeader(const base::StringPiece& key,
                                    const base::StringPiece& value) {
-  DCHECK(HttpUtil::IsValidHeaderName(key));
-  DCHECK(HttpUtil::IsValidHeaderValue(value));
-  HeaderVector::iterator it = FindHeader(key);
-  if (it != headers_.end())
-    it->value.assign(value.data(), value.size());
-  else
-    headers_.push_back(HeaderKeyValuePair(key, value));
+  DCHECK(HttpUtil::IsValidHeaderName(key)) << key;
+  DCHECK(HttpUtil::IsValidHeaderValue(value)) << key << ":" << value;
+  SetHeaderInternal(key, value);
 }
 
 void HttpRequestHeaders::SetHeaderIfMissing(const base::StringPiece& key,
@@ -229,4 +225,13 @@ HttpRequestHeaders::FindHeader(const base::StringPiece& key) const {
   return headers_.end();
 }
 
+void HttpRequestHeaders::SetHeaderInternal(const base::StringPiece& key,
+                                           const base::StringPiece& value) {
+  HeaderVector::iterator it = FindHeader(key);
+  if (it != headers_.end())
+    it->value.assign(value.data(), value.size());
+  else
+    headers_.push_back(HeaderKeyValuePair(key, value));
+}
+
 }  // namespace net
diff --git a/net/http/http_request_headers.h b/net/http/http_request_headers.h
index 3c8a46ce796390..c246f4f10c86ba 100644
--- a/net/http/http_request_headers.h
+++ b/net/http/http_request_headers.h
@@ -28,7 +28,7 @@ class NetLogCaptureMode;
 
 class NET_EXPORT HttpRequestHeaders {
  public:
-  struct HeaderKeyValuePair {
+  struct NET_EXPORT HeaderKeyValuePair {
     HeaderKeyValuePair();
     HeaderKeyValuePair(const base::StringPiece& key,
                        const base::StringPiece& value);
@@ -112,6 +112,12 @@ class NET_EXPORT HttpRequestHeaders {
   // |value| passes HttpUtil::IsValidHeaderValue().
   void SetHeader(const base::StringPiece& key, const base::StringPiece& value);
 
+  // Does the same as above but without internal DCHECKs for validations.
+  void SetHeaderWithoutCheckForTesting(const base::StringPiece& key,
+                                       const base::StringPiece& value) {
+    SetHeaderInternal(key, value);
+  }
+
   // Sets the header value pair for |key| and |value|, if |key| does not exist.
   // If |key| already exists, the call is a no-op.
   // When comparing |key|, case is ignored.
@@ -167,10 +173,15 @@ class NET_EXPORT HttpRequestHeaders {
       const std::string* request_line,
       NetLogCaptureMode capture_mode) const;
 
+  const HeaderVector& GetHeaderVector() const { return headers_; }
+
  private:
   HeaderVector::iterator FindHeader(const base::StringPiece& key);
   HeaderVector::const_iterator FindHeader(const base::StringPiece& key) const;
 
+  void SetHeaderInternal(const base::StringPiece& key,
+                         const base::StringPiece& value);
+
   HeaderVector headers_;
 
   // Allow the copy construction and operator= to facilitate copying in
diff --git a/services/BUILD.gn b/services/BUILD.gn
index 36ede309438141..cc25a7a01122b5 100644
--- a/services/BUILD.gn
+++ b/services/BUILD.gn
@@ -19,6 +19,7 @@ service_test("services_unittests") {
   # section below. If you are unsure, contact blundell@chromium.org.
   deps = [
     "//services/identity:tests",
+    "//services/network/public/cpp:tests",
   ]
 
   if (!is_ios) {
diff --git a/services/network/public/cpp/BUILD.gn b/services/network/public/cpp/BUILD.gn
index cc1393612c445d..65b5ac6377d61c 100644
--- a/services/network/public/cpp/BUILD.gn
+++ b/services/network/public/cpp/BUILD.gn
@@ -2,6 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//mojo/public/tools/bindings/mojom.gni")
+
 static_library("cpp") {
   sources = [
     "net_adapters.cc",
@@ -14,3 +16,27 @@ static_library("cpp") {
     "//net",
   ]
 }
+
+mojom("test_interfaces") {
+  sources = [
+    "network_traits_test_service.mojom",
+  ]
+  public_deps = [
+    "//services/network/public/interfaces",
+  ]
+}
+
+source_set("tests") {
+  testonly = true
+
+  sources = [
+    "network_struct_traits_unittest.cc",
+  ]
+  deps = [
+    ":test_interfaces",
+    "//base",
+    "//mojo/public/cpp/bindings",
+    "//net",
+    "//testing/gtest",
+  ]
+}
diff --git a/services/network/public/cpp/OWNERS b/services/network/public/cpp/OWNERS
new file mode 100644
index 00000000000000..2c44a463856dd1
--- /dev/null
+++ b/services/network/public/cpp/OWNERS
@@ -0,0 +1,6 @@
+per-file *.mojom=set noparent
+per-file *.mojom=file://ipc/SECURITY_OWNERS
+per-file *_struct_traits*.*=set noparent
+per-file *_struct_traits*.*=file://ipc/SECURITY_OWNERS
+per-file *.typemap=set noparent
+per-file *.typemap=file://ipc/SECURITY_OWNERS
diff --git a/services/network/public/cpp/http_request_headers.typemap b/services/network/public/cpp/http_request_headers.typemap
new file mode 100644
index 00000000000000..90c8e67ba2af86
--- /dev/null
+++ b/services/network/public/cpp/http_request_headers.typemap
@@ -0,0 +1,15 @@
+# Copyright 2017 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+mojom = "//services/network/public/interfaces/http_request_headers.mojom"
+public_headers = [ "//net/http/http_request_headers.h" ]
+traits_headers =
+    [ "//services/network/public/cpp/http_request_headers_struct_traits.h" ]
+sources = [
+  "//services/network/public/cpp/http_request_headers_struct_traits.cc",
+]
+public_deps = [
+  "//net",
+]
+type_mappings = [ "network.mojom.HttpRequestHeaders=net::HttpRequestHeaders" ]
diff --git a/services/network/public/cpp/http_request_headers_struct_traits.cc b/services/network/public/cpp/http_request_headers_struct_traits.cc
new file mode 100644
index 00000000000000..5debd751aa918d
--- /dev/null
+++ b/services/network/public/cpp/http_request_headers_struct_traits.cc
@@ -0,0 +1,45 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "services/network/public/cpp/http_request_headers_struct_traits.h"
+
+#include "net/http/http_util.h"
+
+namespace mojo {
+
+// static
+bool StructTraits<network::mojom::HttpRequestHeaderKeyValuePairDataView,
+                  net::HttpRequestHeaders::HeaderKeyValuePair>::
+    Read(network::mojom::HttpRequestHeaderKeyValuePairDataView data,
+         net::HttpRequestHeaders::HeaderKeyValuePair* item) {
+  if (!data.ReadKey(&item->key))
+    return false;
+  if (!net::HttpUtil::IsValidHeaderName(item->key))
+    return false;
+  if (!data.ReadValue(&item->value))
+    return false;
+  item->value = std::string(net::HttpUtil::TrimLWS(item->value));
+  if (!net::HttpUtil::IsValidHeaderValue(item->value))
+    return false;
+  return true;
+}
+
+// static
+bool StructTraits<network::mojom::HttpRequestHeadersDataView,
+                  net::HttpRequestHeaders>::
+    Read(network::mojom::HttpRequestHeadersDataView data,
+         net::HttpRequestHeaders* headers) {
+  ArrayDataView<network::mojom::HttpRequestHeaderKeyValuePairDataView>
+      data_view;
+  data.GetHeadersDataView(&data_view);
+  for (size_t i = 0; i < data_view.size(); ++i) {
+    net::HttpRequestHeaders::HeaderKeyValuePair pair;
+    if (!data_view.Read(i, &pair))
+      return false;
+    headers->SetHeader(pair.key, pair.value);
+  }
+  return true;
+}
+
+}  // namespace mojo
diff --git a/services/network/public/cpp/http_request_headers_struct_traits.h b/services/network/public/cpp/http_request_headers_struct_traits.h
new file mode 100644
index 00000000000000..07b17356c3f87e
--- /dev/null
+++ b/services/network/public/cpp/http_request_headers_struct_traits.h
@@ -0,0 +1,42 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SERVICES_NETWORK_PUBLIC_CPP_HTTP_REQUEST_HEADERS_STRUCT_TRAITS_H_
+#define SERVICES_NETWORK_PUBLIC_CPP_HTTP_REQUEST_HEADERS_STRUCT_TRAITS_H_
+
+#include "mojo/public/cpp/bindings/struct_traits.h"
+#include "net/http/http_request_headers.h"
+#include "services/network/public/interfaces/http_request_headers.mojom.h"
+
+namespace mojo {
+
+template <>
+struct StructTraits<network::mojom::HttpRequestHeaderKeyValuePairDataView,
+                    net::HttpRequestHeaders::HeaderKeyValuePair> {
+  static const std::string& key(
+      const net::HttpRequestHeaders::HeaderKeyValuePair& item) {
+    return item.key;
+  }
+  static const std::string& value(
+      const net::HttpRequestHeaders::HeaderKeyValuePair& item) {
+    return item.value;
+  }
+  static bool Read(network::mojom::HttpRequestHeaderKeyValuePairDataView data,
+                   net::HttpRequestHeaders::HeaderKeyValuePair* item);
+};
+
+template <>
+struct StructTraits<network::mojom::HttpRequestHeadersDataView,
+                    net::HttpRequestHeaders> {
+  static net::HttpRequestHeaders::HeaderVector headers(
+      const net::HttpRequestHeaders& data) {
+    return data.GetHeaderVector();
+  }
+  static bool Read(network::mojom::HttpRequestHeadersDataView data,
+                   net::HttpRequestHeaders* headers);
+};
+
+}  // namespace mojo
+
+#endif  // SERVICES_NETWORK_PUBLIC_CPP_HTTP_REQUEST_HEADERS_STRUCT_TRAITS_H_
diff --git a/services/network/public/cpp/network_struct_traits_unittest.cc b/services/network/public/cpp/network_struct_traits_unittest.cc
new file mode 100644
index 00000000000000..2acaf6c5d36116
--- /dev/null
+++ b/services/network/public/cpp/network_struct_traits_unittest.cc
@@ -0,0 +1,110 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/message_loop/message_loop.h"
+#include "base/strings/string_util.h"
+#include "mojo/public/cpp/bindings/binding_set.h"
+#include "services/network/public/cpp/http_request_headers_struct_traits.h"
+#include "services/network/public/cpp/network_traits_test_service.mojom.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace network {
+
+namespace {
+
+class NetworkStructTraitsTest : public testing::Test,
+                                public mojom::TraitsTestService {
+ protected:
+  NetworkStructTraitsTest() = default;
+
+  mojom::TraitsTestServicePtr GetTraitsTestProxy() {
+    mojom::TraitsTestServicePtr proxy;
+    traits_test_bindings_.AddBinding(this, mojo::MakeRequest(&proxy));
+    return proxy;
+  }
+
+ private:
+  // TraitsTestService:
+  void EchoHttpRequestHeaders(
+      const net::HttpRequestHeaders& header,
+      EchoHttpRequestHeadersCallback callback) override {
+    std::move(callback).Run(header);
+  }
+
+  base::MessageLoop loop_;
+  mojo::BindingSet<TraitsTestService> traits_test_bindings_;
+  DISALLOW_COPY_AND_ASSIGN(NetworkStructTraitsTest);
+};
+
+}  // namespace
+
+TEST_F(NetworkStructTraitsTest, HttpRequestHeaders_Basic) {
+  net::HttpRequestHeaders headers;
+  net::HttpRequestHeaders output;
+  headers.SetHeader("Foo", "bar");
+  mojom::TraitsTestServicePtr proxy = GetTraitsTestProxy();
+  proxy->EchoHttpRequestHeaders(headers, &output);
+  std::string value;
+  EXPECT_TRUE(output.GetHeader("Foo", &value));
+  EXPECT_EQ("bar", value);
+  EXPECT_FALSE(output.HasHeader("Fo"));
+}
+
+TEST_F(NetworkStructTraitsTest, HttpRequestHeaders_InvalidHeaderName) {
+  // Check that non-token chars are disallowed.
+  const unsigned char invalid_name_chars[] = {
+      0x80, 0x19, '(', ')', '<', '>', '@', ',', ';', ':',
+      '\\', '"',  '/', '[', ']', '?', '=', '{', '}'};
+  for (char c : invalid_name_chars) {
+    std::string invalid_name("foo");
+    invalid_name.push_back(c);
+    net::HttpRequestHeaders header;
+    net::HttpRequestHeaders output;
+    header.SetHeaderWithoutCheckForTesting(invalid_name, "foo");
+    mojom::TraitsTestServicePtr proxy = GetTraitsTestProxy();
+    proxy->EchoHttpRequestHeaders(header, &output);
+    std::string value;
+    EXPECT_TRUE(output.IsEmpty());
+  }
+}
+
+// Test cases are copied from HttpUtilTest.IsValidHeaderValue.
+TEST_F(NetworkStructTraitsTest, HttpRequestHeaders_InvalidHeaderValue) {
+  const char* const invalid_values[] = {
+      "X-Requested-With: chrome${NUL}Sec-Unsafe: injected",
+      "X-Requested-With: chrome\r\nSec-Unsafe: injected",
+      "X-Requested-With: chrome\nSec-Unsafe: injected",
+      "X-Requested-With: chrome\rSec-Unsafe: injected",
+  };
+
+  for (const std::string& value : invalid_values) {
+    std::string replaced = value;
+    base::ReplaceSubstringsAfterOffset(&replaced, 0, "${NUL}",
+                                       std::string(1, '\0'));
+    net::HttpRequestHeaders header;
+    net::HttpRequestHeaders output;
+    header.SetHeaderWithoutCheckForTesting("Foo", replaced);
+    mojom::TraitsTestServicePtr proxy = GetTraitsTestProxy();
+    proxy->EchoHttpRequestHeaders(header, &output);
+    EXPECT_FALSE(output.HasHeader("Foo"));
+  }
+
+  // Check that all characters permitted by RFC7230 3.2.6 are allowed.
+  std::string allowed = "\t";
+  for (char c = '\x20'; c < '\x7F'; ++c) {
+    allowed.append(1, c);
+  }
+  for (int c = 0x80; c <= 0xFF; ++c) {
+    allowed.append(1, static_cast<char>(c));
+  }
+
+  net::HttpRequestHeaders header;
+  net::HttpRequestHeaders output;
+  header.SetHeaderWithoutCheckForTesting("Foo", allowed);
+  mojom::TraitsTestServicePtr proxy = GetTraitsTestProxy();
+  proxy->EchoHttpRequestHeaders(header, &output);
+  EXPECT_TRUE(output.HasHeader("Foo"));
+}
+
+}  // namespace network
diff --git a/services/network/public/cpp/network_traits_test_service.mojom b/services/network/public/cpp/network_traits_test_service.mojom
new file mode 100644
index 00000000000000..ab8dae7e6e089f
--- /dev/null
+++ b/services/network/public/cpp/network_traits_test_service.mojom
@@ -0,0 +1,12 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+module network.mojom;
+
+import "services/network/public/interfaces/http_request_headers.mojom";
+
+interface TraitsTestService {
+  [Sync]
+  EchoHttpRequestHeaders(HttpRequestHeaders headers) => (HttpRequestHeaders pass);
+};
diff --git a/services/network/public/cpp/typemaps.gni b/services/network/public/cpp/typemaps.gni
new file mode 100644
index 00000000000000..91ef4571ea4a85
--- /dev/null
+++ b/services/network/public/cpp/typemaps.gni
@@ -0,0 +1,5 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+typemaps = [ "//services/network/public/cpp/http_request_headers.typemap" ]
diff --git a/services/network/public/interfaces/BUILD.gn b/services/network/public/interfaces/BUILD.gn
index f89b5a861916a5..8df1de01625728 100644
--- a/services/network/public/interfaces/BUILD.gn
+++ b/services/network/public/interfaces/BUILD.gn
@@ -7,5 +7,6 @@ import("//mojo/public/tools/bindings/mojom.gni")
 mojom("interfaces") {
   sources = [
     "fetch_api.mojom",
+    "http_request_headers.mojom",
   ]
 }
diff --git a/services/network/public/interfaces/http_request_headers.mojom b/services/network/public/interfaces/http_request_headers.mojom
new file mode 100644
index 00000000000000..5e38006e3e1cb7
--- /dev/null
+++ b/services/network/public/interfaces/http_request_headers.mojom
@@ -0,0 +1,14 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+module network.mojom;
+
+struct HttpRequestHeaderKeyValuePair {
+  string key;
+  string value;
+};
+
+struct HttpRequestHeaders {
+  array<HttpRequestHeaderKeyValuePair> headers;
+};