Move enable_webrtc to a buildflag header.

chrome/common/pref_names.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Constants for the names of various preferences, for easier changing.
 
 #ifndef CHROME_COMMON_PREF_NAMES_H_
 #define CHROME_COMMON_PREF_NAMES_H_
 
 #include <stddef.h>
 
 #include "build/build_config.h"
 #include "chrome/common/features.h"
 #include "extensions/features/features.h"
+#include "media/media_features.h"
 #include "ppapi/features/features.h"
 
 namespace prefs {
 
 // Profile prefs. Please add Local State prefs below instead.
 #if defined(OS_CHROMEOS) && BUILDFLAG(ENABLE_APP_LIST)
 extern const char kArcApps[];
 extern const char kArcBackupRestoreEnabled[];
 extern const char kArcEnabled[];
 extern const char kArcPolicyCompliant[];
@@ skipping 410 matching lines @@
 extern const char kEasyUnlockEnabled[];
 extern const char kEasyUnlockPairing[];
 extern const char kEasyUnlockProximityRequired[];
 
 #if BUILDFLAG(ENABLE_EXTENSIONS)
 extern const char kToolbarIconSurfacingBubbleAcknowledged[];
 extern const char kToolbarIconSurfacingBubbleLastShowTime[];
 extern const char kToolbarMigratedComponentActionStatus[];
 #endif
 
-#if defined(ENABLE_WEBRTC)
+#if BUILDFLAG(ENABLE_WEBRTC)
 extern const char kWebRTCMultipleRoutesEnabled[];
 extern const char kWebRTCNonProxiedUdpEnabled[];
 extern const char kWebRTCIPHandlingPolicy[];
 extern const char kWebRTCUDPPortRange[];
 #endif
 
 #if !defined(OS_ANDROID)
 extern const char kHasSeenWelcomePage[];
 #endif
 
@@ skipping 394 matching lines @@
 
 #if defined(OS_ANDROID)
 extern const char kSearchGeolocationDisclosureDismissed[];
 extern const char kSearchGeolocationDisclosureShownCount[];
 extern const char kSearchGeolocationDisclosureLastShowDate[];
 #endif
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_