Add observers to FrameSinkManagerHost.

content/test/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/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
@@ skipping 1211 matching lines @@
     "../browser/renderer_host/media/media_stream_manager_unittest.cc",
     "../browser/renderer_host/media/media_stream_ui_proxy_unittest.cc",
     "../browser/renderer_host/media/mock_video_capture_provider.cc",
     "../browser/renderer_host/media/mock_video_capture_provider.h",
     "../browser/renderer_host/media/render_frame_audio_output_stream_factory_unittest.cc",
     "../browser/renderer_host/media/renderer_audio_output_stream_factory_context_impl_unittest.cc",
     "../browser/renderer_host/media/video_capture_buffer_pool_unittest.cc",
     "../browser/renderer_host/media/video_capture_controller_unittest.cc",
     "../browser/renderer_host/media/video_capture_manager_unittest.cc",
     "../browser/renderer_host/media/video_capture_unittest.cc",
-    "../browser/renderer_host/offscreen_canvas_compositor_frame_sink_manager_unittest.cc",
+    "../browser/renderer_host/offscreen_canvas_provider_impl_unittest.cc",
     "../browser/renderer_host/render_process_host_unittest.cc",
     "../browser/renderer_host/render_view_host_unittest.cc",
     "../browser/renderer_host/render_widget_host_unittest.cc",
     "../browser/renderer_host/render_widget_host_view_aura_unittest.cc",
     "../browser/renderer_host/render_widget_host_view_base_unittest.cc",
     "../browser/renderer_host/render_widget_host_view_mac_editcommand_helper_unittest.mm",
     "../browser/renderer_host/render_widget_host_view_mac_unittest.mm",
     "../browser/renderer_host/text_input_client_mac_unittest.mm",
     "../browser/resolve_proxy_msg_helper_unittest.cc",
     "../browser/screen_orientation/screen_orientation_provider_unittest.cc",
@@ skipping 581 matching lines @@
   if (is_android) {
     deps += [ "//testing/android/native_test:native_test_native_code" ]
   }
 }
 
 group("fuzzers") {
   deps = [
     "//content/test/fuzzer",
   ]
 }