H.264 video codec support using OpenH264/FFmpeg

webrtc/modules/video_coding/BUILD.gn

Index: webrtc/modules/video_coding/BUILD.gn
diff --git a/webrtc/modules/video_coding/BUILD.gn b/webrtc/modules/video_coding/BUILD.gn
index f321fbc269017c6f1c116a8d31293b9ecbd25d82..115ed3588b90e30a5130517583c85e6e3f3eb4dc 100644
--- a/webrtc/modules/video_coding/BUILD.gn
+++ b/webrtc/modules/video_coding/BUILD.gn
@@ -133,15 +133,19 @@ source_set("webrtc_h264") {
     configs -= [ "//build/config/clang:find_bad_constructs" ]
   }
 
+  defines = []
   deps = [
     "../../system_wrappers",
   ]
 
   if (rtc_use_h264) {
-    # Dependency for sake of compiling and so that variables use_openh264 and
-    # ffmpeg_branding are recognized build arguments (avoid "Build argument has
-    # no effect" error). The variables and dependencies will be used for real as
-    # soon as https://codereview.webrtc.org/1306813009/ lands.
+    defines += [ "WEBRTC_THIRD_PARTY_H264" ]
+    sources += [
+      "codecs/h264/h264_decoder_impl.cc",
+      "codecs/h264/h264_decoder_impl.h",
+      "codecs/h264/h264_encoder_impl.cc",
+      "codecs/h264/h264_encoder_impl.h",
+    ]
     deps += [
       "//third_party/ffmpeg:ffmpeg",
       "//third_party/openh264:encoder",