Move enable_webrtc to a buildflag header.

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index 9caaf4124250991d1c91b5228c3198feda141e74..3b02122611bd9780277972e204e75b338839e0de 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -159,6 +159,7 @@
 #include "device/geolocation/geolocation_provider.h"
 #include "extensions/features/features.h"
 #include "media/base/media_resources.h"
+#include "media/media_features.h"
 #include "net/base/net_module.h"
 #include "net/cookies/cookie_monster.h"
 #include "net/http/http_network_layer.h"
@@ -251,9 +252,9 @@
 #include "components/rlz/rlz_tracker.h"
 #endif  // defined(ENABLE_RLZ)
 
-#if defined(ENABLE_WEBRTC)
+#if BUILDFLAG(ENABLE_WEBRTC)
 #include "chrome/browser/media/webrtc/webrtc_log_util.h"
-#endif  // defined(ENABLE_WEBRTC)
+#endif  // BUILDFLAG(ENABLE_WEBRTC)
 
 #if defined(USE_AURA)
 #include "ui/aura/env.h"
@@ -1383,7 +1384,7 @@ void ChromeBrowserMainParts::PostBrowserStart() {
   // Allow ProcessSingleton to process messages.
   process_singleton_->Unlock();
 #endif  // !defined(OS_ANDROID)
-#if defined(ENABLE_WEBRTC)
+#if BUILDFLAG(ENABLE_WEBRTC)
   // Set up a task to delete old WebRTC log files for all profiles. Use a delay
   // to reduce the impact on startup time.
   BrowserThread::PostDelayedTask(
@@ -1391,7 +1392,7 @@ void ChromeBrowserMainParts::PostBrowserStart() {
       FROM_HERE,
       base::Bind(&WebRtcLogUtil::DeleteOldWebRtcLogFilesForAllProfiles),
       base::TimeDelta::FromMinutes(1));
-#endif  // defined(ENABLE_WEBRTC)
+#endif  // BUILDFLAG(ENABLE_WEBRTC)
 
 #if !defined(OS_ANDROID)
   if (base::FeatureList::IsEnabled(features::kWebUsb)) {