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/buildflag_header.gni")
 import("//build/config/features.gni")
 import("//content/renderer/renderer.gni")
+import("//third_party/webrtc/build/webrtc.gni")
 
 # See //content/BUILD.gn for how this works.
 group("renderer") {
   if (is_component_build) {
     public_deps = [
       "//content",
     ]
   } else {
     public_deps = [
       ":renderer_sources",
     ]
   }
 }
 
+buildflag_header("renderer_features") {
+  header = "renderer_features.h"
+
+  flags = [ "RTC_USE_H264=$rtc_use_h264" ]
+}
+
 source_set("renderer_sources") {
   visibility = [ "//content/*" ]
 
   sources = rebase_path(content_renderer_gypi_values.public_renderer_sources,
                         ".",
                         "//content")
 
   configs += [ "//content:content_implementation" ]
 
   deps = [
@@ skipping 11 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/renderer/media/webrtc:finch_h264_with_openh264_ffmpeg",
+      "//third_party/webrtc",
+    ]
   }
 
   if (enable_plugins) {
     sources +=
         rebase_path(content_renderer_gypi_values.public_renderer_plugin_sources,
                     ".",
                     "//content")
   }
 }