Add watch time metrics for HTML5 media playback.

media/blink/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("//media/media_options.gni")
 import("//testing/test.gni")
 
 component("blink") {
   output_name = "media_blink"
 
@@ skipping 44 matching lines @@
     "new_session_cdm_result_promise.cc",
     "new_session_cdm_result_promise.h",
     "resource_multibuffer_data_provider.cc",
     "resource_multibuffer_data_provider.h",
     "texttrack_impl.cc",
     "texttrack_impl.h",
     "url_index.cc",
     "url_index.h",
     "video_frame_compositor.cc",
     "video_frame_compositor.h",
+    "watch_time_reporter.cc",
+    "watch_time_reporter.h",
     "webaudiosourceprovider_impl.cc",
     "webaudiosourceprovider_impl.h",
     "webcontentdecryptionmodule_impl.cc",
     "webcontentdecryptionmodule_impl.h",
     "webcontentdecryptionmoduleaccess_impl.cc",
     "webcontentdecryptionmoduleaccess_impl.h",
     "webcontentdecryptionmodulesession_impl.cc",
     "webcontentdecryptionmodulesession_impl.h",
     "webencryptedmediaclient_impl.cc",
     "webencryptedmediaclient_impl.h",
@@ skipping 63 matching lines @@
     "mock_weburlloader.cc",
     "mock_weburlloader.h",
     "multibuffer_data_source_unittest.cc",
     "multibuffer_unittest.cc",
     "resource_multibuffer_data_provider_unittest.cc",
     "run_all_unittests.cc",
     "test_response_generator.cc",
     "test_response_generator.h",
     "url_index_unittest.cc",
     "video_frame_compositor_unittest.cc",
+    "watch_time_reporter_unittest.cc",
     "webaudiosourceprovider_impl_unittest.cc",
     "webmediaplayer_impl_unittest.cc",
   ]
 
   if (is_android) {
     deps += [
       "//media/base/android",
       "//media/base/android:media_java",
       "//v8:v8_external_startup_data_assets",
     ]
   }
 }