diff --git a/google_apis/drive/drive_api_requests_unittest.cc b/google_apis/drive/drive_api_requests_unittest.cc
index 0d6831b6e3ef45..61013778f9aa43 100644
--- a/google_apis/drive/drive_api_requests_unittest.cc
+++ b/google_apis/drive/drive_api_requests_unittest.cc
@@ -11,6 +11,7 @@
 #include <memory>
 #include <utility>
 
+#include "base/containers/contains.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
@@ -277,7 +278,7 @@ class DriveApiRequestsTest : public testing::Test {
   std::unique_ptr<net::test_server::HttpResponse> HandleChildrenDeleteRequest(
       const net::test_server::HttpRequest& request) {
     if (request.method != net::test_server::METHOD_DELETE ||
-        request.relative_url.find("/children/") == std::string::npos) {
+        !base::Contains(request.relative_url, "/children/")) {
       // The request is not the "Children: delete" request. Delegate the
       // processing to the next handler.
       return nullptr;
@@ -315,7 +316,7 @@ class DriveApiRequestsTest : public testing::Test {
   std::unique_ptr<net::test_server::HttpResponse> HandleDeleteRequest(
       const net::test_server::HttpRequest& request) {
     if (request.method != net::test_server::METHOD_DELETE ||
-        request.relative_url.find("/files/") == std::string::npos) {
+        !base::Contains(request.relative_url, "/files/")) {
       // The file is not file deletion request. Delegate the processing to the
       // next handler.
       return nullptr;
diff --git a/google_apis/drive/drive_base_requests.cc b/google_apis/drive/drive_base_requests.cc
index ad5934a9b72763..865057b26d1039 100644
--- a/google_apis/drive/drive_base_requests.cc
+++ b/google_apis/drive/drive_base_requests.cc
@@ -10,6 +10,7 @@
 #include <memory>
 #include <utility>
 
+#include "base/containers/contains.h"
 #include "base/files/file_util.h"
 #include "base/functional/bind.h"
 #include "base/json/json_reader.h"
@@ -127,8 +128,8 @@ void GenerateMultipartBody(MultipartType multipart_type,
     while (true) {
       boundary = net::GenerateMimeMultipartBoundary();
       bool conflict_with_content = false;
-      for (auto& part : parts) {
-        if (part.data.find(boundary, 0) != std::string::npos) {
+      for (const auto& part : parts) {
+        if (base::Contains(part.data, boundary)) {
           conflict_with_content = true;
           break;
         }
@@ -152,7 +153,7 @@ void GenerateMultipartBody(MultipartType multipart_type,
   output->data.clear();
   if (data_offset)
     data_offset->clear();
-  for (auto& part : parts) {
+  for (const auto& part : parts) {
     output->data.append(base::StringPrintf(
         kMultipartItemHeaderFormat, boundary.c_str(), part.type.c_str()));
     if (data_offset)
diff --git a/google_apis/gaia/core_account_id.cc b/google_apis/gaia/core_account_id.cc
index 4dad7936aa3e0a..51fbecea39bb47 100644
--- a/google_apis/gaia/core_account_id.cc
+++ b/google_apis/gaia/core_account_id.cc
@@ -5,13 +5,14 @@
 #include "google_apis/gaia/core_account_id.h"
 
 #include "base/check.h"
+#include "base/containers/contains.h"
 #include "google_apis/gaia/gaia_auth_util.h"
 
 namespace {
 // Returns whether the string looks like an email (the test is
 // crude an only checks whether it includes an '@').
 bool IsEmailString(const std::string& string) {
-  return string.find('@') != std::string::npos;
+  return base::Contains(string, '@');
 }
 }  // anonymous namespace
 
@@ -99,4 +100,4 @@ std::vector<std::string> ToStringList(
   for (const auto& account_id : account_ids)
     account_ids_string.push_back(account_id.ToString());
   return account_ids_string;
-}
\ No newline at end of file
+}
diff --git a/google_apis/gaia/fake_gaia.cc b/google_apis/gaia/fake_gaia.cc
index f75abf20d34619..d36880f4799588 100644
--- a/google_apis/gaia/fake_gaia.cc
+++ b/google_apis/gaia/fake_gaia.cc
@@ -659,7 +659,7 @@ void FakeGaia::HandleEmbeddedLookupAccountLookup(
   std::string email;
   const bool is_saml =
       GetQueryParameter(request.content, "identifier", &email) &&
-      saml_account_idp_map_.find(email) != saml_account_idp_map_.end();
+      base::Contains(saml_account_idp_map_, email);
 
   if (!is_saml)
     return;
diff --git a/google_apis/gaia/gaia_auth_fetcher_unittest.cc b/google_apis/gaia/gaia_auth_fetcher_unittest.cc
index a051dd766c3eff..81a03aead774f1 100644
--- a/google_apis/gaia/gaia_auth_fetcher_unittest.cc
+++ b/google_apis/gaia/gaia_auth_fetcher_unittest.cc
@@ -9,6 +9,7 @@
 #include <string>
 #include <vector>
 
+#include "base/containers/contains.h"
 #include "base/functional/bind.h"
 #include "base/json/json_reader.h"
 #include "base/memory/ref_counted.h"
@@ -270,7 +271,7 @@ TEST_F(GaiaAuthFetcherTest, StartAuthCodeForOAuth2TokenExchangeSuccess) {
   EXPECT_EQ(google_apis::GetOmitCredentialsModeForGaiaRequests(),
             received_requests_.at(0).credentials_mode);
   std::string body = GetRequestBodyAsString(&received_requests_.at(0));
-  EXPECT_EQ(std::string::npos, body.find("device_type=chrome"));
+  EXPECT_FALSE(base::Contains(body, "device_type=chrome"));
   EXPECT_TRUE(auth.HasPendingFetch());
 
   auth.TestOnURLLoadCompleteInternal(net::OK, net::HTTP_OK,
@@ -289,8 +290,8 @@ TEST_F(GaiaAuthFetcherTest, StartAuthCodeForOAuth2TokenExchangeDeviceId) {
   EXPECT_EQ(google_apis::GetOmitCredentialsModeForGaiaRequests(),
             received_requests_.at(0).credentials_mode);
   std::string body = GetRequestBodyAsString(&received_requests_.at(0));
-  EXPECT_NE(std::string::npos, body.find("device_type=chrome"));
-  EXPECT_NE(std::string::npos, body.find("device_id=device_ABCDE_1"));
+  EXPECT_TRUE(base::Contains(body, "device_type=chrome"));
+  EXPECT_TRUE(base::Contains(body, "device_id=device_ABCDE_1"));
 }
 
 TEST_F(GaiaAuthFetcherTest,
@@ -308,8 +309,8 @@ TEST_F(GaiaAuthFetcherTest,
   EXPECT_EQ(google_apis::GetOmitCredentialsModeForGaiaRequests(),
             received_requests_.at(0).credentials_mode);
   std::string body = GetRequestBodyAsString(&received_requests_.at(0));
-  EXPECT_NE(std::string::npos,
-            body.find("bound_token_registration_jwt=registration_jwt"));
+  EXPECT_TRUE(
+      base::Contains(body, "bound_token_registration_jwt=registration_jwt"));
   EXPECT_TRUE(auth.HasPendingFetch());
 
   auth.TestOnURLLoadCompleteInternal(net::OK, net::HTTP_OK,
diff --git a/google_apis/gaia/gaia_auth_util.cc b/google_apis/gaia/gaia_auth_util.cc
index a942ada781b46f..ae6e2c464fa065 100644
--- a/google_apis/gaia/gaia_auth_util.cc
+++ b/google_apis/gaia/gaia_auth_util.cc
@@ -9,6 +9,7 @@
 #include <memory>
 
 #include "base/base64url.h"
+#include "base/containers/contains.h"
 #include "base/functional/bind.h"
 #include "base/json/json_reader.h"
 #include "base/logging.h"
@@ -76,7 +77,7 @@ std::string SanitizeEmail(base::StringPiece email_address) {
   std::string sanitized(email_address);
 
   // Apply a default domain if necessary.
-  if (sanitized.find('@') == std::string::npos) {
+  if (!base::Contains(sanitized, '@')) {
     sanitized += '@';
     sanitized += kGmailDomain;
   }
diff --git a/google_apis/gaia/oauth2_access_token_manager_unittest.cc b/google_apis/gaia/oauth2_access_token_manager_unittest.cc
index 2c90db57177951..089220139bcff5 100644
--- a/google_apis/gaia/oauth2_access_token_manager_unittest.cc
+++ b/google_apis/gaia/oauth2_access_token_manager_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "google_apis/gaia/oauth2_access_token_manager.h"
 
+#include "base/containers/contains.h"
 #include "base/memory/ref_counted.h"
 #include "base/test/bind.h"
 #include "base/test/task_environment.h"
@@ -38,8 +39,7 @@ class FakeOAuth2AccessTokenManagerDelegate
       const CoreAccountId& account_id,
       scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory,
       OAuth2AccessTokenConsumer* consumer) override {
-    EXPECT_NE(account_ids_to_refresh_tokens_.find(account_id),
-              account_ids_to_refresh_tokens_.end());
+    EXPECT_TRUE(base::Contains(account_ids_to_refresh_tokens_, account_id));
     return GaiaAccessTokenFetcher::
         CreateExchangeRefreshTokenForAccessTokenInstance(
             consumer, url_loader_factory,
@@ -47,8 +47,7 @@ class FakeOAuth2AccessTokenManagerDelegate
   }
 
   bool HasRefreshToken(const CoreAccountId& account_id) const override {
-    return account_ids_to_refresh_tokens_.find(account_id) !=
-           account_ids_to_refresh_tokens_.end();
+    return base::Contains(account_ids_to_refresh_tokens_, account_id);
   }
 
   scoped_refptr<network::SharedURLLoaderFactory> GetURLLoaderFactory()
diff --git a/google_apis/gcm/engine/gcm_store_impl_unittest.cc b/google_apis/gcm/engine/gcm_store_impl_unittest.cc
index 80b11aebccb1a7..c4f0c969a37af3 100644
--- a/google_apis/gcm/engine/gcm_store_impl_unittest.cc
+++ b/google_apis/gcm/engine/gcm_store_impl_unittest.cc
@@ -12,6 +12,7 @@
 #include <vector>
 
 #include "base/command_line.h"
+#include "base/containers/contains.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
@@ -297,11 +298,9 @@ TEST_F(GCMStoreImplTest, Registrations) {
   LoadGCMStore(gcm_store.get(), &load_result);
 
   ASSERT_EQ(2u, load_result->registrations.size());
-  ASSERT_TRUE(load_result->registrations.find(kAppName) !=
-              load_result->registrations.end());
+  EXPECT_TRUE(base::Contains(load_result->registrations, kAppName));
   EXPECT_EQ(registration, load_result->registrations[kAppName]);
-  ASSERT_TRUE(load_result->registrations.find(kAppName2) !=
-              load_result->registrations.end());
+  EXPECT_TRUE(base::Contains(load_result->registrations, kAppName2));
   EXPECT_EQ(registration2, load_result->registrations[kAppName2]);
 
   gcm_store->RemoveRegistration(
@@ -313,8 +312,7 @@ TEST_F(GCMStoreImplTest, Registrations) {
   LoadGCMStore(gcm_store.get(), &load_result);
 
   ASSERT_EQ(1u, load_result->registrations.size());
-  ASSERT_TRUE(load_result->registrations.find(kAppName) !=
-              load_result->registrations.end());
+  EXPECT_TRUE(base::Contains(load_result->registrations, kAppName));
   EXPECT_EQ(registration, load_result->registrations[kAppName]);
 }
 
@@ -660,11 +658,9 @@ TEST_F(GCMStoreImplTest, HeartbeatInterval) {
   LoadGCMStore(gcm_store.get(), &load_result);
 
   EXPECT_EQ(2UL, load_result->heartbeat_intervals.size());
-  ASSERT_TRUE(load_result->heartbeat_intervals.find(scope1) !=
-              load_result->heartbeat_intervals.end());
+  EXPECT_TRUE(base::Contains(load_result->heartbeat_intervals, scope1));
   EXPECT_EQ(heartbeat1, load_result->heartbeat_intervals[scope1]);
-  ASSERT_TRUE(load_result->heartbeat_intervals.find(scope2) !=
-              load_result->heartbeat_intervals.end());
+  EXPECT_TRUE(base::Contains(load_result->heartbeat_intervals, scope2));
   EXPECT_EQ(heartbeat2, load_result->heartbeat_intervals[scope2]);
 
   gcm_store->RemoveHeartbeatInterval(
@@ -676,8 +672,7 @@ TEST_F(GCMStoreImplTest, HeartbeatInterval) {
   LoadGCMStore(gcm_store.get(), &load_result);
 
   EXPECT_EQ(1UL, load_result->heartbeat_intervals.size());
-  ASSERT_TRUE(load_result->heartbeat_intervals.find(scope1) !=
-              load_result->heartbeat_intervals.end());
+  EXPECT_TRUE(base::Contains(load_result->heartbeat_intervals, scope1));
   EXPECT_EQ(heartbeat1, load_result->heartbeat_intervals[scope1]);
 }
 
@@ -766,10 +761,8 @@ TEST_F(GCMStoreImplTest, InstanceIDData) {
   LoadGCMStore(gcm_store.get(), &load_result);
 
   ASSERT_EQ(2u, load_result->instance_id_data.size());
-  ASSERT_TRUE(load_result->instance_id_data.find(kAppName) !=
-              load_result->instance_id_data.end());
-  ASSERT_TRUE(load_result->instance_id_data.find(kAppName2) !=
-              load_result->instance_id_data.end());
+  EXPECT_TRUE(base::Contains(load_result->instance_id_data, kAppName));
+  EXPECT_TRUE(base::Contains(load_result->instance_id_data, kAppName2));
   EXPECT_EQ(instance_id_data, load_result->instance_id_data[kAppName]);
   EXPECT_EQ(instance_id_data2, load_result->instance_id_data[kAppName2]);
 
@@ -782,8 +775,7 @@ TEST_F(GCMStoreImplTest, InstanceIDData) {
   LoadGCMStore(gcm_store.get(), &load_result);
 
   ASSERT_EQ(1u, load_result->instance_id_data.size());
-  ASSERT_TRUE(load_result->instance_id_data.find(kAppName2) !=
-              load_result->instance_id_data.end());
+  EXPECT_TRUE(base::Contains(load_result->instance_id_data, kAppName2));
   EXPECT_EQ(instance_id_data2, load_result->instance_id_data[kAppName2]);
 }
 
diff --git a/google_apis/gcm/engine/instance_id_delete_token_request_handler.cc b/google_apis/gcm/engine/instance_id_delete_token_request_handler.cc
index 8783ef24ef7f00..2913fc6e859540 100644
--- a/google_apis/gcm/engine/instance_id_delete_token_request_handler.cc
+++ b/google_apis/gcm/engine/instance_id_delete_token_request_handler.cc
@@ -5,6 +5,7 @@
 #include "google_apis/gcm/engine/instance_id_delete_token_request_handler.h"
 
 #include "base/check.h"
+#include "base/containers/contains.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_number_conversions.h"
 #include "google_apis/gcm/base/gcm_util.h"
@@ -52,8 +53,9 @@ void InstanceIDDeleteTokenRequestHandler::BuildRequestBody(std::string* body){
 UnregistrationRequest::Status
 InstanceIDDeleteTokenRequestHandler::ParseResponse(
     const std::string& response) {
-  if (response.find(kTokenPrefix) == std::string::npos)
+  if (!base::Contains(response, kTokenPrefix)) {
     return UnregistrationRequest::RESPONSE_PARSING_FAILED;
+  }
 
   return UnregistrationRequest::SUCCESS;
 }
diff --git a/google_apis/gcm/engine/registration_request.cc b/google_apis/gcm/engine/registration_request.cc
index 36adf30acbb6f5..3ea57da31dffaf 100644
--- a/google_apis/gcm/engine/registration_request.cc
+++ b/google_apis/gcm/engine/registration_request.cc
@@ -8,6 +8,7 @@
 
 #include <utility>
 
+#include "base/containers/contains.h"
 #include "base/functional/bind.h"
 #include "base/location.h"
 #include "base/metrics/histogram.h"
@@ -53,20 +54,27 @@ const char kTooManyRegistrations[] = "TOO_MANY_REGISTRATIONS";
 
 // Gets correct status from the error message.
 RegistrationRequest::Status GetStatusFromError(const std::string& error) {
-  if (error.find(kDeviceRegistrationError) != std::string::npos)
+  if (base::Contains(error, kDeviceRegistrationError)) {
     return RegistrationRequest::DEVICE_REGISTRATION_ERROR;
-  if (error.find(kAuthenticationFailed) != std::string::npos)
+  }
+  if (base::Contains(error, kAuthenticationFailed)) {
     return RegistrationRequest::AUTHENTICATION_FAILED;
-  if (error.find(kInvalidSender) != std::string::npos)
+  }
+  if (base::Contains(error, kInvalidSender)) {
     return RegistrationRequest::INVALID_SENDER;
-  if (error.find(kInvalidParameters) != std::string::npos)
+  }
+  if (base::Contains(error, kInvalidParameters)) {
     return RegistrationRequest::INVALID_PARAMETERS;
-  if (error.find(kInternalServerError) != std::string::npos)
+  }
+  if (base::Contains(error, kInternalServerError)) {
     return RegistrationRequest::INTERNAL_SERVER_ERROR;
-  if (error.find(kQuotaExceeded) != std::string::npos)
+  }
+  if (base::Contains(error, kQuotaExceeded)) {
     return RegistrationRequest::QUOTA_EXCEEDED;
-  if (error.find(kTooManyRegistrations) != std::string::npos)
+  }
+  if (base::Contains(error, kTooManyRegistrations)) {
     return RegistrationRequest::TOO_MANY_REGISTRATIONS;
+  }
   // Should not be reached, unless the server adds new error types.
   return RegistrationRequest::UNKNOWN_ERROR;
 }
diff --git a/google_apis/gcm/engine/unregistration_request.cc b/google_apis/gcm/engine/unregistration_request.cc
index 195f5a97f37ef7..cdda15d082bac5 100644
--- a/google_apis/gcm/engine/unregistration_request.cc
+++ b/google_apis/gcm/engine/unregistration_request.cc
@@ -6,6 +6,7 @@
 
 #include <utility>
 
+#include "base/containers/contains.h"
 #include "base/functional/bind.h"
 #include "base/location.h"
 #include "base/strings/escape.h"
@@ -47,12 +48,15 @@ const char kDeviceRegistrationError[] = "PHONE_REGISTRATION_ERROR";
 
 // Gets correct status from the error message.
 UnregistrationRequest::Status GetStatusFromError(const std::string& error) {
-  if (error.find(kInvalidParameters) != std::string::npos)
+  if (base::Contains(error, kInvalidParameters)) {
     return UnregistrationRequest::INVALID_PARAMETERS;
-  if (error.find(kInternalServerError) != std::string::npos)
+  }
+  if (base::Contains(error, kInternalServerError)) {
     return UnregistrationRequest::INTERNAL_SERVER_ERROR;
-  if (error.find(kDeviceRegistrationError) != std::string::npos)
+  }
+  if (base::Contains(error, kDeviceRegistrationError)) {
     return UnregistrationRequest::DEVICE_REGISTRATION_ERROR;
+  }
   // Should not be reached, unless the server adds new error types.
   return UnregistrationRequest::UNKNOWN_ERROR;
 }