Move enable_webrtc to a buildflag header.

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 824f1b636f0d3a2c3d07cf96e77a6f8afc320513..4b5efee258a68aa18baedd489352bdb3483c70a6 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -151,6 +151,7 @@
 #include "media/blink/url_index.h"
 #include "media/blink/webencryptedmediaclient_impl.h"
 #include "media/blink/webmediaplayer_impl.h"
+#include "media/media_features.h"
 #include "media/renderers/gpu_video_accelerator_factories.h"
 #include "mojo/edk/js/core.h"
 #include "mojo/edk/js/support.h"
@@ -216,7 +217,7 @@
 #include "content/renderer/pepper/plugin_module.h"
 #endif
 
-#if defined(ENABLE_WEBRTC)
+#if BUILDFLAG(ENABLE_WEBRTC)
 #include "content/renderer/media/rtc_peer_connection_handler.h"
 #endif
 
@@ -4423,7 +4424,7 @@ blink::WebPushClient* RenderFrameImpl::pushClient() {
 
 void RenderFrameImpl::willStartUsingPeerConnectionHandler(
     blink::WebRTCPeerConnectionHandler* handler) {
-#if defined(ENABLE_WEBRTC)
+#if BUILDFLAG(ENABLE_WEBRTC)
   static_cast<RTCPeerConnectionHandler*>(handler)->associateWithFrame(frame_);
 #endif
 }
@@ -5940,7 +5941,7 @@ void RenderFrameImpl::InitializeUserMediaClient() {
   if (!RenderThreadImpl::current())  // Will be NULL during unit tests.
     return;
 
-#if defined(ENABLE_WEBRTC)
+#if BUILDFLAG(ENABLE_WEBRTC)
   DCHECK(!web_user_media_client_);
   web_user_media_client_ = new UserMediaClientImpl(
       this, RenderThreadImpl::current()->GetPeerConnectionDependencyFactory(),
@@ -5954,7 +5955,7 @@ WebMediaPlayer* RenderFrameImpl::CreateWebMediaPlayerForMediaStream(
     WebMediaPlayerClient* client,
     const WebString& sink_id,
     const WebSecurityOrigin& security_origin) {
-#if defined(ENABLE_WEBRTC)
+#if BUILDFLAG(ENABLE_WEBRTC)
   RenderThreadImpl* const render_thread = RenderThreadImpl::current();
 
   scoped_refptr<base::SingleThreadTaskRunner> compositor_task_runner =
@@ -5971,7 +5972,7 @@ WebMediaPlayer* RenderFrameImpl::CreateWebMediaPlayerForMediaStream(
       sink_id, security_origin);
 #else
   return NULL;
-#endif  // defined(ENABLE_WEBRTC)
+#endif  // BUILDFLAG(ENABLE_WEBRTC)
 }
 
 std::unique_ptr<MediaStreamRendererFactory>
@@ -5980,7 +5981,7 @@ RenderFrameImpl::CreateRendererFactory() {
       GetContentClient()->renderer()->CreateMediaStreamRendererFactory();
   if (factory.get())
     return factory;
-#if defined(ENABLE_WEBRTC)
+#if BUILDFLAG(ENABLE_WEBRTC)
   return std::unique_ptr<MediaStreamRendererFactory>(
       new MediaStreamRendererFactoryImpl());
 #else