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

content/content.gyp

Index: content/content.gyp
diff --git a/content/content.gyp b/content/content.gyp
index 6b11ac2fd58512e405931a1b6156d4dcd2ddcc83..d5591a41d0f5bdba2542b6eefffd2487835428b2 100644
--- a/content/content.gyp
+++ b/content/content.gyp
@@ -23,8 +23,8 @@
   },
   'targets': [
     {
-      # GN version: //content/renderer:renderer_features
-      'target_name': 'renderer_features',
+      # GN version: //content/public/common:common_features
+      'target_name': 'common_features',
       'includes': [
         '../build/buildflag_header.gypi',
         '../third_party/webrtc/build/common.gypi',
@@ -37,7 +37,7 @@
         # TODO(hbos): crbug.com/584219
         ['1==1', {
           'variables': {
-            'buildflag_header_path': 'content/renderer/renderer_features.h',
+            'buildflag_header_path': 'content/public/common/common_features.h',
             'buildflag_flags': [
               'RTC_USE_H264=<(rtc_use_h264)',
             ],
@@ -45,6 +45,19 @@
         }],
       ],
     },
+    {
+      # GN version: //content/public/common:feature_h264_with_openh264_ffmpeg
+      'target_name': 'feature_h264_with_openh264_ffmpeg',
+      'type': 'static_library',
+      'include_dirs': [ '<@(DEPTH)' ],
+      'deps': [
+        ':common_features',
+      ],
+      'sources': [
+        'public/common/feature_h264_with_openh264_ffmpeg.cc',
+        'public/common/feature_h264_with_openh264_ffmpeg.h',
+      ],
+    },
   ],
   'conditions': [
     ['OS != "ios"', {
@@ -285,10 +298,10 @@
               ],
               'dependencies': [
                 '../third_party/webrtc/modules/modules.gyp:webrtc_h264',
+                'common_features',
                 'content_child',
                 'content_common',
                 'content_resources',
-                'renderer_features',
               ],
               'export_dependent_settings': [
                 'content_common',
@@ -328,8 +341,8 @@
           'variables': { 'enable_wexit_time_destructors': 1, },
           'dependencies': [
             '../third_party/webrtc/modules/modules.gyp:webrtc_h264',
+            'common_features',
             'content_resources',
-            'renderer_features',
           ],
           'conditions': [
             ['chromium_enable_vtune_jit_for_v8==1', {