Convert USE(NATIVE_FULLSCREEN_VIDEO) to a runtime enabled feature

content/browser/android/content_startup_flags.cc

 // 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.
 
 #include "content/browser/android/content_startup_flags.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "cc/base/switches.h"
@@ skipping 44 matching lines @@
   parsed_command_line->AppendSwitch(switches::kEnableAcceleratedOverflowScroll);
   parsed_command_line->AppendSwitch(
       switches::kEnableAcceleratedScrollableFrames);
   parsed_command_line->AppendSwitch(
       switches::kEnableCompositedScrollingForFrames);
   parsed_command_line->AppendSwitch(switches::kEnableBeginFrameScheduling);
   parsed_command_line->AppendSwitch(switches::kEnableDeadlineScheduling);
 
   parsed_command_line->AppendSwitch(switches::kEnableGestureTapHighlight);
   parsed_command_line->AppendSwitch(switches::kEnablePinch);
+  parsed_command_line->AppendSwitch(switches::kEnableOverlayFullscreenVideo);
+  parsed_command_line->AppendSwitch(switches::kEnableOverlayScrollbars);
   parsed_command_line->AppendSwitch(switches::kEnableOverscrollNotifications);
-  parsed_command_line->AppendSwitch(switches::kEnableOverlayScrollbars);
 
   // Run the GPU service as a thread in the browser instead of as a
   // standalone process.
   parsed_command_line->AppendSwitch(switches::kInProcessGPU);
   parsed_command_line->AppendSwitch(switches::kDisableGpuShaderDiskCache);
 
   // Always use fixed layout and viewport tag.
   parsed_command_line->AppendSwitch(switches::kEnableFixedLayout);
   parsed_command_line->AppendSwitch(switches::kEnableViewport);
 
   // Disable <canvas> path antialiasing.
   parsed_command_line->AppendSwitch(switches::kDisable2dCanvasAntialiasing);
 
   // Disable anti-aliasing.
   parsed_command_line->AppendSwitch(
       cc::switches::kDisableCompositedAntialiasing);
 
   if (!plugin_descriptor.empty()) {
     parsed_command_line->AppendSwitchNative(
       switches::kRegisterPepperPlugins, plugin_descriptor);
   }
 }
 
 }  // namespace content