diff --git a/chrome/app/chrome_main_delegate.cc b/chrome/app/chrome_main_delegate.cc
index 131e0fa62b03db..b4c6d9bc5b8335 100644
--- a/chrome/app/chrome_main_delegate.cc
+++ b/chrome/app/chrome_main_delegate.cc
@@ -505,6 +505,13 @@ ChromeMainDelegate::ChromeMainDelegate(base::TimeTicks exe_entry_point_ticks) {
 ChromeMainDelegate::~ChromeMainDelegate() {
 }
 
+#if !defined(CHROME_MULTIPLE_DLL_CHILD)
+void ChromeMainDelegate::PostEarlyInitialization() {
+  DCHECK(chrome_feature_list_creator_);
+  chrome_feature_list_creator_->CreateFeatureList();
+}
+#endif
+
 bool ChromeMainDelegate::BasicStartupComplete(int* exit_code) {
 #if defined(OS_CHROMEOS)
   chromeos::BootTimesRecorder::Get()->SaveChromeMainStats();
@@ -1054,9 +1061,13 @@ ChromeMainDelegate::CreateContentBrowserClient() {
 #else
   if (chrome_content_browser_client_ == nullptr) {
     DCHECK(service_manifest_data_pack_);
+    DCHECK(!chrome_feature_list_creator_);
+    chrome_feature_list_creator_ = std::make_unique<ChromeFeatureListCreator>();
+
     chrome_content_browser_client_ =
         std::make_unique<ChromeContentBrowserClient>(
-            std::move(service_manifest_data_pack_));
+            std::move(service_manifest_data_pack_),
+            chrome_feature_list_creator_.get());
   }
   return chrome_content_browser_client_.get();
 #endif
@@ -1139,7 +1150,7 @@ service_manager::ProcessType ChromeMainDelegate::OverrideProcessType() {
   return service_manager::ProcessType::kDefault;
 }
 
-void ChromeMainDelegate::PreContentInitialization() {
+void ChromeMainDelegate::PreCreateMainMessageLoop() {
 #if defined(OS_MACOSX)
   // Tell Cocoa to finish its initialization, which we want to do manually
   // instead of calling NSApplicationMain(). The primary reason is that NSAM()
diff --git a/chrome/app/chrome_main_delegate.h b/chrome/app/chrome_main_delegate.h
index 8931381b45002e..59d8d1b8db9255 100644
--- a/chrome/app/chrome_main_delegate.h
+++ b/chrome/app/chrome_main_delegate.h
@@ -15,6 +15,10 @@
 #include "content/public/app/content_main_delegate.h"
 #include "ui/base/resource/data_pack.h"
 
+#if !defined(CHROME_MULTIPLE_DLL_CHILD)
+#include "chrome/browser/chrome_feature_list_creator.h"
+#endif
+
 namespace base {
 class CommandLine;
 }
@@ -35,7 +39,7 @@ class ChromeMainDelegate : public content::ContentMainDelegate {
   ~ChromeMainDelegate() override;
 
  protected:
-  // content::ContentMainDelegate implementation:
+  // content::ContentMainDelegate:
   bool BasicStartupComplete(int* exit_code) override;
   void PreSandboxStartup() override;
   void SandboxInitialized(const std::string& process_type) override;
@@ -56,7 +60,10 @@ class ChromeMainDelegate : public content::ContentMainDelegate {
 #endif
   bool ShouldEnableProfilerRecording() override;
   service_manager::ProcessType OverrideProcessType() override;
-  void PreContentInitialization() override;
+  void PreCreateMainMessageLoop() override;
+#if !defined(CHROME_MULTIPLE_DLL_CHILD)
+  void PostEarlyInitialization() override;
+#endif
 
   content::ContentBrowserClient* CreateContentBrowserClient() override;
   content::ContentGpuClient* CreateContentGpuClient() override;
@@ -78,6 +85,10 @@ class ChromeMainDelegate : public content::ContentMainDelegate {
   // ContentBrowserClient in CreateContentBrowserClient()
   std::unique_ptr<ui::DataPack> service_manifest_data_pack_;
 
+#if !defined(CHROME_MULTIPLE_DLL_CHILD)
+  std::unique_ptr<ChromeFeatureListCreator> chrome_feature_list_creator_;
+#endif
+
   DISALLOW_COPY_AND_ASSIGN(ChromeMainDelegate);
 };
 
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 2ac9ab73e9f15d..3e8b5fdb9bba50 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -255,6 +255,8 @@ jumbo_split_static_library("browser") {
     "chrome_content_browser_client_parts.h",
     "chrome_device_client.cc",
     "chrome_device_client.h",
+    "chrome_feature_list_creator.cc",
+    "chrome_feature_list_creator.h",
     "chrome_notification_types.h",
     "chrome_quota_permission_context.cc",
     "chrome_quota_permission_context.h",
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index a5c171d5856997..4be2ac1a1a59a1 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -215,8 +215,10 @@ rappor::RapporService* GetBrowserRapporService() {
   return nullptr;
 }
 
-BrowserProcessImpl::BrowserProcessImpl()
-    : pref_service_factory_(
+BrowserProcessImpl::BrowserProcessImpl(
+    scoped_refptr<PersistentPrefStore> user_pref_store)
+    : user_pref_store_(std::move(user_pref_store)),
+      pref_service_factory_(
           std::make_unique<prefs::InProcessPrefServiceFactory>()) {
   g_browser_process = this;
   platform_part_ = std::make_unique<BrowserProcessPlatformPart>();
@@ -1118,7 +1120,7 @@ void BrowserProcessImpl::CreateLocalState() {
   delegate->InitPrefRegistry(pref_registry.get());
   local_state_ = chrome_prefs::CreateLocalState(
       local_state_path, policy_service(), std::move(pref_registry), false,
-      std::move(delegate));
+      std::move(delegate), std::move(user_pref_store_));
   DCHECK(local_state_);
 
   sessions::SessionIdGenerator::GetInstance()->Init(local_state_.get());
diff --git a/chrome/browser/browser_process_impl.h b/chrome/browser/browser_process_impl.h
index 6bfe753fb70a13..f2f961c30d2770 100644
--- a/chrome/browser/browser_process_impl.h
+++ b/chrome/browser/browser_process_impl.h
@@ -25,6 +25,7 @@
 #include "chrome/common/buildflags.h"
 #include "components/keep_alive_registry/keep_alive_state_observer.h"
 #include "components/nacl/common/buildflags.h"
+#include "components/prefs/persistent_pref_store.h"
 #include "components/prefs/pref_change_registrar.h"
 #include "extensions/buildflags/buildflags.h"
 #include "media/media_buildflags.h"
@@ -74,7 +75,11 @@ class TabLifecycleUnitSource;
 class BrowserProcessImpl : public BrowserProcess,
                            public KeepAliveStateObserver {
  public:
-  BrowserProcessImpl();
+  // |user_pref_store|: if non-null, will be used as the source (and
+  // destination) of user prefs for Local State instead of loading the JSON file
+  // from disk.
+  explicit BrowserProcessImpl(
+      scoped_refptr<PersistentPrefStore> user_pref_store);
   ~BrowserProcessImpl() override;
 
   // Called to complete initialization.
@@ -318,6 +323,11 @@ class BrowserProcessImpl : public BrowserProcess,
 
   scoped_refptr<DownloadRequestLimiter> download_request_limiter_;
 
+  // A pref store that is created from the Local State file. This is handed-off
+  // to |local_state_| when it's created. It will use it, if non-null, instead
+  // of loading the user prefs from disk.
+  scoped_refptr<PersistentPrefStore> user_pref_store_;
+
   // Ensures that the observers of plugin/print disable/enable state
   // notifications are properly added and removed.
   PrefChangeRegistrar pref_change_registrar_;
diff --git a/chrome/browser/browser_process_impl_unittest.cc b/chrome/browser/browser_process_impl_unittest.cc
index 3a7af6450b0e22..75d5d38b690dd1 100644
--- a/chrome/browser/browser_process_impl_unittest.cc
+++ b/chrome/browser/browser_process_impl_unittest.cc
@@ -13,6 +13,7 @@
 #include "base/task/task_scheduler/task_scheduler.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
+#include "chrome/browser/chrome_feature_list_creator.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/webui/ntp/ntp_resource_cache_factory.h"
 #include "chrome/test/base/testing_profile.h"
@@ -30,12 +31,19 @@ class BrowserProcessImplTest : public ::testing::Test {
       : stashed_browser_process_(g_browser_process),
         loop_(base::MessageLoop::TYPE_UI),
         ui_thread_(content::BrowserThread::UI, &loop_),
-        command_line_(base::CommandLine::NO_PROGRAM),
-        browser_process_impl_(new BrowserProcessImpl()) {
+        command_line_(base::CommandLine::NO_PROGRAM) {
     // Create() and StartWithDefaultParams() TaskScheduler in seperate steps to
     // properly simulate the browser process' lifecycle.
     base::TaskScheduler::Create("BrowserProcessImplTest");
     base::SetRecordActionTaskRunner(loop_.task_runner());
+
+    // |chrome_feature_list_creator_->CreatePrefServiceForTesting()| creates a
+    // user pref store, and must occur before creating |browser_process_impl_|.
+    chrome_feature_list_creator_ = std::make_unique<ChromeFeatureListCreator>();
+    chrome_feature_list_creator_->CreatePrefServiceForTesting();
+
+    browser_process_impl_ = std::make_unique<BrowserProcessImpl>(
+        chrome_feature_list_creator_->GetPrefStore());
     browser_process_impl_->SetApplicationLocale("en");
   }
 
@@ -98,6 +106,7 @@ class BrowserProcessImplTest : public ::testing::Test {
   std::unique_ptr<content::TestBrowserThread> io_thread_;
   base::CommandLine command_line_;
   std::unique_ptr<content::TestServiceManagerContext> service_manager_context_;
+  std::unique_ptr<ChromeFeatureListCreator> chrome_feature_list_creator_;
   std::unique_ptr<BrowserProcessImpl> browser_process_impl_;
 };
 
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index a1b23ae7dd2781..14e00dd7f9c833 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -20,7 +20,6 @@
 #include "base/debug/crash_logging.h"
 #include "base/debug/debugger.h"
 #include "base/debug/leak_annotations.h"
-#include "base/deferred_sequenced_task_runner.h"
 #include "base/feature_list.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
@@ -32,8 +31,6 @@
 #include "base/metrics/histogram_macros.h"
 #include "base/path_service.h"
 #include "base/run_loop.h"
-#include "base/sequenced_task_runner.h"
-#include "base/single_thread_task_runner.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
@@ -57,6 +54,7 @@
 #include "chrome/browser/browser_process_platform_part.h"
 #include "chrome/browser/chrome_browser_field_trials.h"
 #include "chrome/browser/chrome_browser_main_extra_parts.h"
+#include "chrome/browser/chrome_feature_list_creator.h"
 #include "chrome/browser/component_updater/crl_set_component_installer.h"
 #include "chrome/browser/component_updater/file_type_policies_component_installer.h"
 #include "chrome/browser/component_updater/mei_preload_component_installer.h"
@@ -404,9 +402,9 @@ void InitializeLocalState() {
       registry->RegisterStringPref(language::prefs::kApplicationLocale,
                                    std::string());
       const std::unique_ptr<PrefService> parent_local_state =
-          chrome_prefs::CreateLocalState(parent_profile,
-                                         g_browser_process->policy_service(),
-                                         std::move(registry), false, nullptr);
+          chrome_prefs::CreateLocalState(
+              parent_profile, g_browser_process->policy_service(),
+              std::move(registry), false, nullptr, nullptr);
       // Right now, we only inherit the locale setting from the parent profile.
       local_state->SetString(
           language::prefs::kApplicationLocale,
@@ -782,7 +780,8 @@ const char kMissingLocaleDataMessage[] =
 
 ChromeBrowserMainParts::ChromeBrowserMainParts(
     const content::MainFunctionParams& parameters,
-    std::unique_ptr<ui::DataPack> data_pack)
+    std::unique_ptr<ui::DataPack> data_pack,
+    ChromeFeatureListCreator* chrome_feature_list_creator)
     : parameters_(parameters),
       parsed_command_line_(parameters.command_line),
       result_code_(service_manager::RESULT_CODE_NORMAL_EXIT),
@@ -791,7 +790,9 @@ ChromeBrowserMainParts::ChromeBrowserMainParts(
           !parameters.ui_task),
       profile_(NULL),
       run_message_loop_(true),
-      service_manifest_data_pack_(std::move(data_pack)) {
+      service_manifest_data_pack_(std::move(data_pack)),
+      chrome_feature_list_creator_(chrome_feature_list_creator) {
+  DCHECK(chrome_feature_list_creator_);
   // If we're running tests (ui_task is non-null).
   if (parameters.ui_task)
     browser_defaults::enable_help_app = false;
@@ -989,7 +990,10 @@ int ChromeBrowserMainParts::PreEarlyInitialization() {
   for (size_t i = 0; i < chrome_extra_parts_.size(); ++i)
     chrome_extra_parts_[i]->PreEarlyInitialization();
 
-  browser_process_ = std::make_unique<BrowserProcessImpl>();
+  // Create BrowserProcess in PreEarlyInitialization() so that we can load
+  // field trials (and all it depends upon).
+  browser_process_ = std::make_unique<BrowserProcessImpl>(
+      chrome_feature_list_creator_->GetPrefStore());
 
   bool failed_to_load_resource_bundle = false;
   const int load_local_state_result =
diff --git a/chrome/browser/chrome_browser_main.h b/chrome/browser/chrome_browser_main.h
index 4d0e815c2195d8..b31d95a4144258 100644
--- a/chrome/browser/chrome_browser_main.h
+++ b/chrome/browser/chrome_browser_main.h
@@ -21,6 +21,7 @@
 
 class BrowserProcessImpl;
 class ChromeBrowserMainExtraParts;
+class ChromeFeatureListCreator;
 class FieldTrialSynchronizer;
 class PrefService;
 class Profile;
@@ -55,8 +56,9 @@ class ChromeBrowserMainParts : public content::BrowserMainParts {
 #endif
 
  protected:
-  explicit ChromeBrowserMainParts(const content::MainFunctionParams& parameters,
-                                  std::unique_ptr<ui::DataPack> data_pack);
+  ChromeBrowserMainParts(const content::MainFunctionParams& parameters,
+                         std::unique_ptr<ui::DataPack> data_pack,
+                         ChromeFeatureListCreator* chrome_feature_list_creator);
 
   // content::BrowserMainParts overrides.
   bool ShouldContentCreateFeatureList() override;
@@ -206,6 +208,8 @@ class ChromeBrowserMainParts : public content::BrowserMainParts {
   // resource bundle gets created.
   std::unique_ptr<ui::DataPack> service_manifest_data_pack_;
 
+  ChromeFeatureListCreator* chrome_feature_list_creator_;
+
   DISALLOW_COPY_AND_ASSIGN(ChromeBrowserMainParts);
 };
 
diff --git a/chrome/browser/chrome_browser_main_android.cc b/chrome/browser/chrome_browser_main_android.cc
index fa700a5b78b124..2c5148b7b1d6b4 100644
--- a/chrome/browser/chrome_browser_main_android.cc
+++ b/chrome/browser/chrome_browser_main_android.cc
@@ -35,8 +35,11 @@
 
 ChromeBrowserMainPartsAndroid::ChromeBrowserMainPartsAndroid(
     const content::MainFunctionParams& parameters,
-    std::unique_ptr<ui::DataPack> data_pack)
-    : ChromeBrowserMainParts(parameters, std::move(data_pack)) {}
+    std::unique_ptr<ui::DataPack> data_pack,
+    ChromeFeatureListCreator* chrome_feature_list_creator)
+    : ChromeBrowserMainParts(parameters,
+                             std::move(data_pack),
+                             chrome_feature_list_creator) {}
 
 ChromeBrowserMainPartsAndroid::~ChromeBrowserMainPartsAndroid() {
 }
diff --git a/chrome/browser/chrome_browser_main_android.h b/chrome/browser/chrome_browser_main_android.h
index 7cf7c8cbccd7b9..74516a7cbf00cc 100644
--- a/chrome/browser/chrome_browser_main_android.h
+++ b/chrome/browser/chrome_browser_main_android.h
@@ -11,9 +11,10 @@
 
 class ChromeBrowserMainPartsAndroid : public ChromeBrowserMainParts {
  public:
-  explicit ChromeBrowserMainPartsAndroid(
+  ChromeBrowserMainPartsAndroid(
       const content::MainFunctionParams& parameters,
-      std::unique_ptr<ui::DataPack> data_pack);
+      std::unique_ptr<ui::DataPack> data_pack,
+      ChromeFeatureListCreator* chrome_feature_list_creator);
   ~ChromeBrowserMainPartsAndroid() override;
 
   // content::BrowserMainParts overrides.
diff --git a/chrome/browser/chrome_browser_main_linux.cc b/chrome/browser/chrome_browser_main_linux.cc
index ab9bf625af11df..829f522f6be781 100644
--- a/chrome/browser/chrome_browser_main_linux.cc
+++ b/chrome/browser/chrome_browser_main_linux.cc
@@ -35,8 +35,11 @@
 
 ChromeBrowserMainPartsLinux::ChromeBrowserMainPartsLinux(
     const content::MainFunctionParams& parameters,
-    std::unique_ptr<ui::DataPack> data_pack)
-    : ChromeBrowserMainPartsPosix(parameters, std::move(data_pack)) {}
+    std::unique_ptr<ui::DataPack> data_pack,
+    ChromeFeatureListCreator* chrome_feature_list_creator)
+    : ChromeBrowserMainPartsPosix(parameters,
+                                  std::move(data_pack),
+                                  chrome_feature_list_creator) {}
 
 ChromeBrowserMainPartsLinux::~ChromeBrowserMainPartsLinux() {
 }
diff --git a/chrome/browser/chrome_browser_main_linux.h b/chrome/browser/chrome_browser_main_linux.h
index cfbdda63d02c33..a52adddd65f6f8 100644
--- a/chrome/browser/chrome_browser_main_linux.h
+++ b/chrome/browser/chrome_browser_main_linux.h
@@ -13,9 +13,10 @@
 
 class ChromeBrowserMainPartsLinux : public ChromeBrowserMainPartsPosix {
  public:
-  explicit ChromeBrowserMainPartsLinux(
+  ChromeBrowserMainPartsLinux(
       const content::MainFunctionParams& parameters,
-      std::unique_ptr<ui::DataPack> data_pack);
+      std::unique_ptr<ui::DataPack> data_pack,
+      ChromeFeatureListCreator* chrome_feature_list_creator);
   ~ChromeBrowserMainPartsLinux() override;
 
   // ChromeBrowserMainParts overrides.
diff --git a/chrome/browser/chrome_browser_main_mac.h b/chrome/browser/chrome_browser_main_mac.h
index 5cd8d8e0239cc3..8bc804c1e6d9fe 100644
--- a/chrome/browser/chrome_browser_main_mac.h
+++ b/chrome/browser/chrome_browser_main_mac.h
@@ -10,9 +10,10 @@
 
 class ChromeBrowserMainPartsMac : public ChromeBrowserMainPartsPosix {
  public:
-  explicit ChromeBrowserMainPartsMac(
+  ChromeBrowserMainPartsMac(
       const content::MainFunctionParams& parameters,
-      std::unique_ptr<ui::DataPack> data_pack);
+      std::unique_ptr<ui::DataPack> data_pack,
+      ChromeFeatureListCreator* chrome_feature_list_creator);
   ~ChromeBrowserMainPartsMac() override;
 
   // BrowserParts overrides.
diff --git a/chrome/browser/chrome_browser_main_mac.mm b/chrome/browser/chrome_browser_main_mac.mm
index 689f151aaa1b23..616f8f8273a677 100644
--- a/chrome/browser/chrome_browser_main_mac.mm
+++ b/chrome/browser/chrome_browser_main_mac.mm
@@ -68,8 +68,11 @@ void EnsureMetadataNeverIndexFile(const base::FilePath& user_data_dir) {
 
 ChromeBrowserMainPartsMac::ChromeBrowserMainPartsMac(
     const content::MainFunctionParams& parameters,
-    std::unique_ptr<ui::DataPack> data_pack)
-    : ChromeBrowserMainPartsPosix(parameters, std::move(data_pack)) {}
+    std::unique_ptr<ui::DataPack> data_pack,
+    ChromeFeatureListCreator* chrome_feature_list_creator)
+    : ChromeBrowserMainPartsPosix(parameters,
+                                  std::move(data_pack),
+                                  chrome_feature_list_creator) {}
 
 ChromeBrowserMainPartsMac::~ChromeBrowserMainPartsMac() {
 }
diff --git a/chrome/browser/chrome_browser_main_posix.cc b/chrome/browser/chrome_browser_main_posix.cc
index 94b0a0b2b983b1..a7a9b05d9ec127 100644
--- a/chrome/browser/chrome_browser_main_posix.cc
+++ b/chrome/browser/chrome_browser_main_posix.cc
@@ -109,8 +109,11 @@ void ExitHandler::Exit() {
 
 ChromeBrowserMainPartsPosix::ChromeBrowserMainPartsPosix(
     const content::MainFunctionParams& parameters,
-    std::unique_ptr<ui::DataPack> data_pack)
-    : ChromeBrowserMainParts(parameters, std::move(data_pack)) {}
+    std::unique_ptr<ui::DataPack> data_pack,
+    ChromeFeatureListCreator* chrome_feature_list_creator)
+    : ChromeBrowserMainParts(parameters,
+                             std::move(data_pack),
+                             chrome_feature_list_creator) {}
 
 int ChromeBrowserMainPartsPosix::PreEarlyInitialization() {
   const int result = ChromeBrowserMainParts::PreEarlyInitialization();
diff --git a/chrome/browser/chrome_browser_main_posix.h b/chrome/browser/chrome_browser_main_posix.h
index 334a2fc6567e8d..f5d497ae358693 100644
--- a/chrome/browser/chrome_browser_main_posix.h
+++ b/chrome/browser/chrome_browser_main_posix.h
@@ -10,9 +10,10 @@
 
 class ChromeBrowserMainPartsPosix : public ChromeBrowserMainParts {
  public:
-  explicit ChromeBrowserMainPartsPosix(
+  ChromeBrowserMainPartsPosix(
       const content::MainFunctionParams& parameters,
-      std::unique_ptr<ui::DataPack> data_pack);
+      std::unique_ptr<ui::DataPack> data_pack,
+      ChromeFeatureListCreator* chrome_feature_list_creator);
 
   // content::BrowserMainParts overrides.
   int PreEarlyInitialization() override;
diff --git a/chrome/browser/chrome_browser_main_win.cc b/chrome/browser/chrome_browser_main_win.cc
index cc39c3d7e54029..ea4e613ed3d454 100644
--- a/chrome/browser/chrome_browser_main_win.cc
+++ b/chrome/browser/chrome_browser_main_win.cc
@@ -457,8 +457,11 @@ int DoUninstallTasks(bool chrome_still_running) {
 
 ChromeBrowserMainPartsWin::ChromeBrowserMainPartsWin(
     const content::MainFunctionParams& parameters,
-    std::unique_ptr<ui::DataPack> data_pack)
-    : ChromeBrowserMainParts(parameters, std::move(data_pack)) {}
+    std::unique_ptr<ui::DataPack> data_pack,
+    ChromeFeatureListCreator* chrome_feature_list_creator)
+    : ChromeBrowserMainParts(parameters,
+                             std::move(data_pack),
+                             chrome_feature_list_creator) {}
 
 ChromeBrowserMainPartsWin::~ChromeBrowserMainPartsWin() {
 }
diff --git a/chrome/browser/chrome_browser_main_win.h b/chrome/browser/chrome_browser_main_win.h
index 4dc9464dcf85e4..2865cdf4cf51dc 100644
--- a/chrome/browser/chrome_browser_main_win.h
+++ b/chrome/browser/chrome_browser_main_win.h
@@ -26,9 +26,10 @@ int DoUninstallTasks(bool chrome_still_running);
 
 class ChromeBrowserMainPartsWin : public ChromeBrowserMainParts {
  public:
-  explicit ChromeBrowserMainPartsWin(
+  ChromeBrowserMainPartsWin(
       const content::MainFunctionParams& parameters,
-      std::unique_ptr<ui::DataPack> data_pack);
+      std::unique_ptr<ui::DataPack> data_pack,
+      ChromeFeatureListCreator* chrome_feature_list_creator);
 
   ~ChromeBrowserMainPartsWin() override;
 
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index fe334be866e239..a794342b6885bc 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -988,8 +988,11 @@ std::unique_ptr<service_manager::Service> CreatePrefService(
 }  // namespace
 
 ChromeContentBrowserClient::ChromeContentBrowserClient(
-    std::unique_ptr<ui::DataPack> data_pack)
-    : weak_factory_(this) {
+    std::unique_ptr<ui::DataPack> data_pack,
+    ChromeFeatureListCreator* chrome_feature_list_creator)
+    : service_manifest_data_pack_(std::move(data_pack)),
+      chrome_feature_list_creator_(chrome_feature_list_creator),
+      weak_factory_(this) {
 #if BUILDFLAG(ENABLE_PLUGINS)
   for (size_t i = 0; i < arraysize(kPredefinedAllowedDevChannelOrigins); ++i)
     allowed_dev_channel_origins_.insert(kPredefinedAllowedDevChannelOrigins[i]);
@@ -1017,8 +1020,6 @@ ChromeContentBrowserClient::ChromeContentBrowserClient(
   gpu_binder_registry_.AddInterface(
       base::Bind(&metrics::CallStackProfileCollector::Create,
                  metrics::CallStackProfileParams::GPU_PROCESS));
-
-  service_manifest_data_pack_ = std::move(data_pack);
 }
 
 ChromeContentBrowserClient::~ChromeContentBrowserClient() {
@@ -1080,26 +1081,33 @@ content::BrowserMainParts* ChromeContentBrowserClient::CreateBrowserMainParts(
   // Construct the Main browser parts based on the OS type.
 #if defined(OS_WIN)
   main_parts = new ChromeBrowserMainPartsWin(
-      parameters, std::move(service_manifest_data_pack_));
+      parameters, std::move(service_manifest_data_pack_),
+      chrome_feature_list_creator_);
 #elif defined(OS_MACOSX)
   main_parts = new ChromeBrowserMainPartsMac(
-      parameters, std::move(service_manifest_data_pack_));
+      parameters, std::move(service_manifest_data_pack_),
+      chrome_feature_list_creator_);
 #elif defined(OS_CHROMEOS)
   main_parts = new chromeos::ChromeBrowserMainPartsChromeos(
-      parameters, std::move(service_manifest_data_pack_));
+      parameters, std::move(service_manifest_data_pack_),
+      chrome_feature_list_creator_);
 #elif defined(OS_LINUX)
   main_parts = new ChromeBrowserMainPartsLinux(
-      parameters, std::move(service_manifest_data_pack_));
+      parameters, std::move(service_manifest_data_pack_),
+      chrome_feature_list_creator_);
 #elif defined(OS_ANDROID)
   main_parts = new ChromeBrowserMainPartsAndroid(
-      parameters, std::move(service_manifest_data_pack_));
+      parameters, std::move(service_manifest_data_pack_),
+      chrome_feature_list_creator_);
 #elif defined(OS_POSIX)
   main_parts = new ChromeBrowserMainPartsPosix(
-      parameters, std::move(service_manifest_data_pack_));
+      parameters, std::move(service_manifest_data_pack_),
+      chrome_feature_list_creator_);
 #else
   NOTREACHED();
   main_parts = new ChromeBrowserMainParts(
-      parameters, std::move(service_manifest_data_pack_));
+      parameters, std::move(service_manifest_data_pack_),
+      chrome_feature_list_creator_);
 #endif
 
   chrome::AddProfilesExtraParts(main_parts);
diff --git a/chrome/browser/chrome_content_browser_client.h b/chrome/browser/chrome_content_browser_client.h
index 2ab8cbb42c827c..a063582d9d4333 100644
--- a/chrome/browser/chrome_content_browser_client.h
+++ b/chrome/browser/chrome_content_browser_client.h
@@ -18,6 +18,7 @@
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "build/build_config.h"
+#include "chrome/browser/chrome_feature_list_creator.h"
 #include "chrome/browser/chrome_service.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/common/resource_type.h"
@@ -67,7 +68,8 @@ class Origin;
 class ChromeContentBrowserClient : public content::ContentBrowserClient {
  public:
   explicit ChromeContentBrowserClient(
-      std::unique_ptr<ui::DataPack> data_pack = nullptr);
+      std::unique_ptr<ui::DataPack> data_pack = nullptr,
+      ChromeFeatureListCreator* chrome_feature_list_creator = nullptr);
   ~ChromeContentBrowserClient() override;
 
   // TODO(https://crbug.com/787567): This file is about calls from content/ out
@@ -575,6 +577,8 @@ class ChromeContentBrowserClient : public content::ContentBrowserClient {
 
   std::unique_ptr<ui::DataPack> service_manifest_data_pack_;
 
+  ChromeFeatureListCreator* chrome_feature_list_creator_;
+
   base::WeakPtrFactory<ChromeContentBrowserClient> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeContentBrowserClient);
diff --git a/chrome/browser/chrome_feature_list_creator.cc b/chrome/browser/chrome_feature_list_creator.cc
new file mode 100644
index 00000000000000..44ba341d99db21
--- /dev/null
+++ b/chrome/browser/chrome_feature_list_creator.cc
@@ -0,0 +1,47 @@
+// Copyright 2018 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 "chrome/browser/chrome_feature_list_creator.h"
+
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/path_service.h"
+#include "chrome/common/chrome_paths.h"
+#include "components/prefs/json_pref_store.h"
+#include "components/prefs/pref_registry.h"
+#include "components/prefs/pref_registry_simple.h"
+#include "components/prefs/pref_service_factory.h"
+#include "components/variations/pref_names.h"
+
+ChromeFeatureListCreator::ChromeFeatureListCreator() = default;
+ChromeFeatureListCreator::~ChromeFeatureListCreator() = default;
+
+void ChromeFeatureListCreator::CreatePrefService() {
+  base::FilePath local_state_file;
+  bool result =
+      base::PathService::Get(chrome::FILE_LOCAL_STATE, &local_state_file);
+  DCHECK(result);
+
+  pref_store_ = base::MakeRefCounted<JsonPrefStore>(local_state_file);
+  pref_store_->ReadPrefs();
+
+  PrefServiceFactory factory;
+  factory.set_user_prefs(pref_store_);
+
+  scoped_refptr<PrefRegistry> registry = new PrefRegistrySimple();
+  simple_local_state_ = factory.Create(registry);
+}
+
+scoped_refptr<PersistentPrefStore> ChromeFeatureListCreator::GetPrefStore() {
+  return pref_store_;
+}
+
+void ChromeFeatureListCreator::CreateFeatureList() {
+  CreatePrefService();
+  // TODO(hanxi): Add implementation to create feature list.
+}
+
+void ChromeFeatureListCreator::CreatePrefServiceForTesting() {
+  CreatePrefService();
+}
diff --git a/chrome/browser/chrome_feature_list_creator.h b/chrome/browser/chrome_feature_list_creator.h
new file mode 100644
index 00000000000000..9d8b0f80ec16ba
--- /dev/null
+++ b/chrome/browser/chrome_feature_list_creator.h
@@ -0,0 +1,38 @@
+// Copyright 2018 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 CHROME_BROWSER_CHROME_FEATURE_LIST_CREATOR_H_
+#define CHROME_BROWSER_CHROME_FEATURE_LIST_CREATOR_H_
+
+#include "base/macros.h"
+#include "components/prefs/pref_service.h"
+
+// Responsible for creating feature list and all its necessary parameters.
+// This class is currently WIP and doesn't do what it's meant to do.
+// TODO(hanxi): Finish implementation, https://crbug.com/848615.
+class ChromeFeatureListCreator {
+ public:
+  ChromeFeatureListCreator();
+  ~ChromeFeatureListCreator();
+
+  // Gets the pref store that is used to create feature list.
+  scoped_refptr<PersistentPrefStore> GetPrefStore();
+
+  // Initializes all necessary parameters to create the feature list and calls
+  // base::FeatureList::SetInstance() to set the global instance.
+  void CreateFeatureList();
+
+  void CreatePrefServiceForTesting();
+
+ private:
+  void CreatePrefService();
+
+  scoped_refptr<PersistentPrefStore> pref_store_;
+
+  std::unique_ptr<PrefService> simple_local_state_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChromeFeatureListCreator);
+};
+
+#endif  // CHROME_BROWSER_CHROME_FEATURE_LIST_CREATOR_H_
diff --git a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
index 2ef649e859dfdd..9b622394215754 100644
--- a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
+++ b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
@@ -537,8 +537,11 @@ class SystemTokenCertDBInitializer {
 
 ChromeBrowserMainPartsChromeos::ChromeBrowserMainPartsChromeos(
     const content::MainFunctionParams& parameters,
-    std::unique_ptr<ui::DataPack> data_pack)
-    : ChromeBrowserMainPartsLinux(parameters, std::move(data_pack)) {}
+    std::unique_ptr<ui::DataPack> data_pack,
+    ChromeFeatureListCreator* chrome_feature_list_creator)
+    : ChromeBrowserMainPartsLinux(parameters,
+                                  std::move(data_pack),
+                                  chrome_feature_list_creator) {}
 
 ChromeBrowserMainPartsChromeos::~ChromeBrowserMainPartsChromeos() {
   // To be precise, logout (browser shutdown) is not yet done, but the
diff --git a/chrome/browser/chromeos/chrome_browser_main_chromeos.h b/chrome/browser/chromeos/chrome_browser_main_chromeos.h
index 02effbebb2cf90..8180bbd15a73a3 100644
--- a/chrome/browser/chromeos/chrome_browser_main_chromeos.h
+++ b/chrome/browser/chromeos/chrome_browser_main_chromeos.h
@@ -68,9 +68,10 @@ class UserActivityController;
 // src/ash or chrome/browser/ui/ash.
 class ChromeBrowserMainPartsChromeos : public ChromeBrowserMainPartsLinux {
  public:
-  explicit ChromeBrowserMainPartsChromeos(
+  ChromeBrowserMainPartsChromeos(
       const content::MainFunctionParams& parameters,
-      std::unique_ptr<ui::DataPack> data_pack);
+      std::unique_ptr<ui::DataPack> data_pack,
+      ChromeFeatureListCreator* chrome_feature_list_creator);
   ~ChromeBrowserMainPartsChromeos() override;
 
   // ChromeBrowserMainParts overrides.
diff --git a/chrome/browser/prefs/chrome_pref_service_factory.cc b/chrome/browser/prefs/chrome_pref_service_factory.cc
index bc3f0abdef7f83..c22257afc995a8 100644
--- a/chrome/browser/prefs/chrome_pref_service_factory.cc
+++ b/chrome/browser/prefs/chrome_pref_service_factory.cc
@@ -456,14 +456,20 @@ std::unique_ptr<PrefService> CreateLocalState(
     policy::PolicyService* policy_service,
     scoped_refptr<PrefRegistry> pref_registry,
     bool async,
-    std::unique_ptr<PrefValueStore::Delegate> delegate) {
+    std::unique_ptr<PrefValueStore::Delegate> delegate,
+    scoped_refptr<PersistentPrefStore> user_pref_store) {
+  if (!user_pref_store) {
+    // The new JsonPrefStore will read content from |pref_filename| in
+    // PrefServiceSyncableFactory. Errors are ignored.
+    user_pref_store = base::MakeRefCounted<JsonPrefStore>(
+        pref_filename, std::unique_ptr<PrefFilter>());
+  }
   sync_preferences::PrefServiceSyncableFactory factory;
-  PrepareFactory(
-      &factory, pref_filename, policy_service,
-      nullptr,  // supervised_user_settings
-      new JsonPrefStore(pref_filename, std::unique_ptr<PrefFilter>()),
-      nullptr,  // extension_prefs
-      async);
+  PrepareFactory(&factory, pref_filename, policy_service,
+                 nullptr,  // supervised_user_settings
+                 std::move(user_pref_store),
+                 nullptr,  // extension_prefs
+                 async);
   return factory.Create(std::move(pref_registry), std::move(delegate));
 }
 
diff --git a/chrome/browser/prefs/chrome_pref_service_factory.h b/chrome/browser/prefs/chrome_pref_service_factory.h
index 8020d4631ecb86..3318afc9909f7f 100644
--- a/chrome/browser/prefs/chrome_pref_service_factory.h
+++ b/chrome/browser/prefs/chrome_pref_service_factory.h
@@ -64,12 +64,15 @@ extern const char kSettingsEnforcementGroupEnforceAlwaysWithExtensionsAndDSE[];
 // guaranteed that in asynchronous version initialization happens after this
 // function returned.
 
+// |user_pref_store| instance is an existing pref store that the local state
+// PrefService uses as its persistent user pref store.
 std::unique_ptr<PrefService> CreateLocalState(
     const base::FilePath& pref_filename,
     policy::PolicyService* policy_service,
     scoped_refptr<PrefRegistry> pref_registry,
     bool async,
-    std::unique_ptr<PrefValueStore::Delegate> delegate);
+    std::unique_ptr<PrefValueStore::Delegate> delegate,
+    scoped_refptr<PersistentPrefStore> user_pref_store);
 
 std::unique_ptr<sync_preferences::PrefServiceSyncable> CreateProfilePrefs(
     const base::FilePath& pref_filename,
diff --git a/content/app/content_main_runner_impl.cc b/content/app/content_main_runner_impl.cc
index 58e5e03f3f6585..145dc521064f61 100644
--- a/content/app/content_main_runner_impl.cc
+++ b/content/app/content_main_runner_impl.cc
@@ -877,7 +877,7 @@ int ContentMainRunnerImpl::Run(bool start_service_manager_only) {
       base::TaskScheduler::Create("Browser");
     }
 
-    delegate_->PreContentInitialization();
+    delegate_->PreCreateMainMessageLoop();
 
     // Create a MessageLoop if one does not already exist for the current
     // thread. This thread won't be promoted as BrowserThread::UI until
@@ -885,6 +885,7 @@ int ContentMainRunnerImpl::Run(bool start_service_manager_only) {
     if (!base::MessageLoopCurrentForUI::IsSet())
       main_message_loop_ = std::make_unique<base::MessageLoopForUI>();
 
+    delegate_->PostEarlyInitialization();
     return RunBrowserProcessMain(main_params, delegate_);
   }
 #endif  // !defined(CHROME_MULTIPLE_DLL_CHILD)
diff --git a/content/public/app/content_main_delegate.h b/content/public/app/content_main_delegate.h
index 979e25d1c1b9ff..4231027909279b 100644
--- a/content/public/app/content_main_delegate.h
+++ b/content/public/app/content_main_delegate.h
@@ -125,10 +125,14 @@ class CONTENT_EXPORT ContentMainDelegate {
       const base::Closure& quit_closure,
       service_manager::BackgroundServiceManager* service_manager);
 
+  // Allows the embedder to perform platform-specific initializatioion before
+  // creating the main message loop.
+  virtual void PreCreateMainMessageLoop() {}
+
   // Allows the embedder to perform platform-specific initializatioion. For
-  // example, things that should be done immediately before the creation of the
-  // main message loop.
-  virtual void PreContentInitialization() {}
+  // example, things that should be done right after TaskScheduler starts and
+  // the main MessageLoop was installed.
+  virtual void PostEarlyInitialization() {}
 
  protected:
   friend class ContentClientInitializer;
diff --git a/content/shell/app/shell_main_delegate.cc b/content/shell/app/shell_main_delegate.cc
index b1e09521e8ad8b..2cd909585ccb3d 100644
--- a/content/shell/app/shell_main_delegate.cc
+++ b/content/shell/app/shell_main_delegate.cc
@@ -414,7 +414,7 @@ void ShellMainDelegate::InitializeResourceBundle() {
 #endif
 }
 
-void ShellMainDelegate::PreContentInitialization() {
+void ShellMainDelegate::PreCreateMainMessageLoop() {
 #if defined(OS_ANDROID)
   base::CommandLine& command_line = *base::CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(switches::kRunWebTests) ||
diff --git a/content/shell/app/shell_main_delegate.h b/content/shell/app/shell_main_delegate.h
index 8be636128699f9..97373efe723001 100644
--- a/content/shell/app/shell_main_delegate.h
+++ b/content/shell/app/shell_main_delegate.h
@@ -36,7 +36,7 @@ class ShellMainDelegate : public ContentMainDelegate {
 #if defined(OS_LINUX)
   void ZygoteForked() override;
 #endif
-  void PreContentInitialization() override;
+  void PreCreateMainMessageLoop() override;
   ContentBrowserClient* CreateContentBrowserClient() override;
   ContentGpuClient* CreateContentGpuClient() override;
   ContentRendererClient* CreateContentRendererClient() override;
diff --git a/extensions/shell/app/shell_main_delegate.h b/extensions/shell/app/shell_main_delegate.h
index 9a0776801c1077..1a0a6c1e0db9ac 100644
--- a/extensions/shell/app/shell_main_delegate.h
+++ b/extensions/shell/app/shell_main_delegate.h
@@ -41,7 +41,7 @@ class ShellMainDelegate : public content::ContentMainDelegate {
   void ZygoteForked() override;
 #endif
 #if defined(OS_MACOSX)
-  void PreContentInitialization() override;
+  void PreCreateMainMessageLoop() override;
 #endif
 
  private:
diff --git a/extensions/shell/app/shell_main_delegate_mac.mm b/extensions/shell/app/shell_main_delegate_mac.mm
index a3bb4a330ab773..b8f12a42ba7d5e 100644
--- a/extensions/shell/app/shell_main_delegate_mac.mm
+++ b/extensions/shell/app/shell_main_delegate_mac.mm
@@ -8,7 +8,7 @@
 
 namespace extensions {
 
-void ShellMainDelegate::PreContentInitialization() {
+void ShellMainDelegate::PreCreateMainMessageLoop() {
   // Force the NSApplication subclass to be used.
   [ShellCrApplication sharedApplication];
 }
diff --git a/headless/lib/headless_content_main_delegate.h b/headless/lib/headless_content_main_delegate.h
index a5b63e7812814f..540bb685ae323d 100644
--- a/headless/lib/headless_content_main_delegate.h
+++ b/headless/lib/headless_content_main_delegate.h
@@ -44,7 +44,7 @@ class HEADLESS_EXPORT HeadlessContentMainDelegate
       const std::string& process_type,
       const content::MainFunctionParams& main_function_params) override;
 #if defined(OS_MACOSX)
-  void PreContentInitialization() override;
+  void PreCreateMainMessageLoop() override;
 #endif
   content::ContentBrowserClient* CreateContentBrowserClient() override;
   content::ContentUtilityClient* CreateContentUtilityClient() override;
diff --git a/headless/lib/headless_content_main_delegate_mac.mm b/headless/lib/headless_content_main_delegate_mac.mm
index afc99df7301152..39211500af0d77 100644
--- a/headless/lib/headless_content_main_delegate_mac.mm
+++ b/headless/lib/headless_content_main_delegate_mac.mm
@@ -8,7 +8,7 @@
 
 namespace headless {
 
-void HeadlessContentMainDelegate::PreContentInitialization() {
+void HeadlessContentMainDelegate::PreCreateMainMessageLoop() {
   // Force the NSApplication subclass to be used.
   [HeadlessShellCrApplication sharedApplication];
 }