Add missing header files to GN files

content/public/renderer/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/features.gni")
 import("//media/media_options.gni")
 import("//ppapi/features/features.gni")
 
 # See //content/BUILD.gn for how this works.
 group("renderer") {
@@ skipping 13 matching lines @@
 } else {
   link_target_type = "static_library"
 }
 target(link_target_type, "renderer_sources") {
   # External code should depend on via ":renderer" above.
   visibility = [ "//content/*" ]
 
   sources = [
     "android_content_detection_prefixes.cc",
     "android_content_detection_prefixes.h",
+    "associated_resource_fetcher.h",
     "browser_plugin_delegate.cc",
     "browser_plugin_delegate.h",
     "chrome_object_extensions_utils.cc",
     "chrome_object_extensions_utils.h",
     "content_renderer_client.cc",
     "content_renderer_client.h",
     "context_menu_client.h",
     "document_state.cc",
     "document_state.h",
     "navigation_state.cc",
     "navigation_state.h",
     "pepper_plugin_instance.h",
     "platform_event_observer.h",
+    "plugin_instance_throttler.h",
     "render_accessibility.h",
     "render_frame.h",
     "render_frame_observer.cc",
     "render_frame_observer.h",
     "render_frame_observer_tracker.h",
     "render_thread.cc",
     "render_thread.h",
     "render_thread_observer.cc",
     "render_thread_observer.h",
     "render_view.h",
@@ skipping 55 matching lines @@
     deps += [
       "//content/public/common:feature_h264_with_openh264_ffmpeg",
       "//content/public/common:features",
     ]
   }
 
   if (enable_plugins) {
     sources += [ "plugin_instance_throttler.h" ]
   }
 }