Enable H.264 video WebRTC behind run-time flag and add WebRtcBrowserTest for H.264

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("//content/renderer/renderer.gni")
 
 # See //content/BUILD.gn for how this works.
 group("renderer") {
   if (is_component_build) {
@@ skipping 31 matching lines @@
     # This target is a pair with content/renderer. They always go together and
     # include headers from each other.
     "//content/renderer",
   ]
 
   if (enable_webrtc) {
     sources +=
         rebase_path(content_renderer_gypi_values.public_renderer_webrtc_sources,
                     ".",
                     "//content")
-    deps += [ "//third_party/webrtc" ]
+    deps += [
+      "//content/public/common:common_features",
+      "//content/public/common:feature_h264_with_openh264_ffmpeg",
+      "//third_party/webrtc",
+    ]
   }
 
   if (enable_plugins) {
     sources +=
         rebase_path(content_renderer_gypi_values.public_renderer_plugin_sources,
                     ".",
                     "//content")
   }
 }