Convert USE(NATIVE_FULLSCREEN_VIDEO) to a runtime enabled feature

content/public/common/content_switches.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.
 
 // Defines all the "content" command-line switches.
 
 #ifndef CONTENT_PUBLIC_COMMON_CONTENT_SWITCHES_H_
 #define CONTENT_PUBLIC_COMMON_CONTENT_SWITCHES_H_
 
 #include "build/build_config.h"
@@ skipping 120 matching lines @@
  #if defined(OS_WIN)
 extern const char kEnableHighResolutionTime[];
 #endif
 extern const char kEnableHTMLImports[];
 CONTENT_EXPORT extern const char kEnableInbandTextTracks[];
 extern const char kEnableInputModeAttribute[];
 CONTENT_EXPORT extern const char kEnableLogging[];
 extern const char kEnableMemoryBenchmarking[];
 extern const char kEnableMonitorProfile[];
 CONTENT_EXPORT extern const char kEnableOfflineCacheAccess[];
+CONTENT_EXPORT extern const char kEnableOverlayFullscreenVideo[];
 extern const char kEnableOverlayScrollbars[];
 CONTENT_EXPORT extern const char kEnableOverscrollNotifications[];
 extern const char kEnablePinch[];
 extern const char kEnablePreparsedJsCaching[];
 CONTENT_EXPORT extern const char kEnablePrivilegedWebGLExtensions[];
 extern const char kEnablePruneGpuCommandBuffers[];
 CONTENT_EXPORT extern const char kEnableRegionBasedColumns[];
 extern const char kEnableSandboxLogging[];
 extern const char kEnableSkiaBenchmarking[];
 CONTENT_EXPORT extern const char kEnableSmoothScrolling[];
@@ skipping 140 matching lines @@
 #if defined(USE_AURA)
 CONTENT_EXPORT extern const char kTestCompositor[];
 #endif
 
 // DON'T ADD RANDOM STUFF HERE. Put it in the main section above in
 // alphabetical order, or in one of the ifdefs (also in order in each section).
 
 }  // namespace switches
 
 #endif  // CONTENT_PUBLIC_COMMON_CONTENT_SWITCHES_H_