Run the later parts of startup as UI thread tasks

content/content_browser.gypi

Index: content/content_browser.gypi
diff --git a/content/content_browser.gypi b/content/content_browser.gypi
index d1d088265d8d48979bdad505d6399b80e7e54fcc..30388b19a31ea8d20789af199db974b39d0b9918 100644
--- a/content/content_browser.gypi
+++ b/content/content_browser.gypi
@@ -237,6 +237,7 @@
     'browser/android/browser_jni_registrar.h',
     'browser/android/browser_media_player_manager.cc',
     'browser/android/browser_media_player_manager.h',
+    'browser/android/browser_startup_configuration_android.cc',
     'browser/android/child_process_launcher_android.cc',
     'browser/android/child_process_launcher_android.h',
     'browser/android/content_settings.cc',
@@ -315,6 +316,8 @@
     'browser/browser_process_sub_thread.cc',
     'browser/browser_process_sub_thread.h',
     'browser/browser_thread_impl.cc',
+    'browser/browser_startup_configuration.cc',
+    'browser/browser_startup_configuration.h',
     'browser/browser_thread_impl.h',
     'browser/browser_url_handler_impl.cc',
     'browser/browser_url_handler_impl.h',
@@ -1034,6 +1037,8 @@
     'browser/ssl/ssl_policy.h',
     'browser/ssl/ssl_request_info.cc',
     'browser/ssl/ssl_request_info.h',
+    'browser/startup_task_runner.cc',
+    'browser/startup_task_runner.h',
     'browser/streams/stream.cc',
     'browser/streams/stream.h',
     'browser/streams/stream_context.cc',
@@ -1351,6 +1356,7 @@
         ['exclude', '^browser/geolocation/network_location_request\\.(cc|h)$'],
         ['exclude', '^browser/tracing/tracing_ui'],
         ['exclude', '^browser/speech/'],
+        ['exclude', '^browser/browser_startup_configuration.cc'],
         ['include', '^browser/speech/speech_recognition_dispatcher_host\\.(cc|h)$'],
         ['include', '^browser/speech/speech_recognition_manager_impl\\.(cc|h)$'],
         ['include', '^browser/speech/speech_recognizer\\.h$'],