Move enable_webrtc to a buildflag header.

content/public/browser/gpu_utils.cc

Index: content/public/browser/gpu_utils.cc
diff --git a/content/public/browser/gpu_utils.cc b/content/public/browser/gpu_utils.cc
index d8b70417c8313c50f0136e017a95b00a3bae7855..7ac9c72396a2b8ba4677285c3b9dc820d2273f6b 100644
--- a/content/public/browser/gpu_utils.cc
+++ b/content/public/browser/gpu_utils.cc
@@ -9,6 +9,7 @@
 #include "content/public/common/content_switches.h"
 #include "gpu/command_buffer/service/gpu_switches.h"
 #include "gpu/config/gpu_switches.h"
+#include "media/media_features.h"
 #include "ui/gl/gl_switches.h"
 
 namespace {
@@ -43,7 +44,7 @@ const gpu::GpuPreferences GetGpuPreferencesFromCommandLine() {
   gpu_preferences.disable_vaapi_accelerated_video_encode =
       command_line->HasSwitch(switches::kDisableVaapiAcceleratedVideoEncode);
 #endif
-#if defined(ENABLE_WEBRTC)
+#if BUILDFLAG(ENABLE_WEBRTC)
   gpu_preferences.disable_web_rtc_hw_encoding =
       command_line->HasSwitch(switches::kDisableWebRtcHWEncoding) &&
       command_line->GetSwitchValueASCII(switches::kDisableWebRtcHWEncoding)