Preparation CL for H264 support in WebRTC.

content/renderer/BUILD.gn

Index: content/renderer/BUILD.gn
diff --git a/content/renderer/BUILD.gn b/content/renderer/BUILD.gn
index b08f9ddf5dd341792de19fde8fe8ef72833ef423..3a90a06fe145f7ce20e7a605dc0fac3032eacd31 100644
--- a/content/renderer/BUILD.gn
+++ b/content/renderer/BUILD.gn
@@ -6,6 +6,7 @@ import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//content/renderer/renderer.gni")
 import("//media/media_options.gni")
+import("//third_party/webrtc/build/webrtc.gni")
 
 source_set("renderer") {
   # Only the public target should depend on this. All other targets (even
@@ -170,6 +171,10 @@ source_set("renderer") {
       "//third_party/webrtc/modules/audio_processing",
       "//third_party/webrtc/system_wrappers",
     ]
+
+    if (rtc_use_h264) {
+      defines += [ "WEBRTC_USE_H264" ]
+    }
   } else {
     sources += [
       "media/webrtc_logging.h",