Convert USE(NATIVE_FULLSCREEN_VIDEO) to a runtime enabled feature

content/shell/browser/webkit_test_controller.cc

 // Copyright 2013 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/shell/browser/webkit_test_controller.h"
 
 #include <iostream>
 
 #include "base/base64.h"
 #include "base/command_line.h"
@@ skipping 499 matching lines @@
   // image is really expensive.
   if (actual_pixel_hash != expected_pixel_hash_) {
     std::vector<unsigned char> png;
 
     // Only the expected PNGs for Mac have a valid alpha channel.
 #if defined(OS_MACOSX)
     bool discard_transparency = false;
 #else
     bool discard_transparency = true;
 #endif
+    if (CommandLine::ForCurrentProcess()->HasSwitch(
+        switches::kEnableOverlayFullscreenVideo))
+      discard_transparency = false;
 
     std::vector<gfx::PNGCodec::Comment> comments;
     comments.push_back(gfx::PNGCodec::Comment("checksum", actual_pixel_hash));
     bool success = gfx::PNGCodec::Encode(
         static_cast<const unsigned char*>(image.getPixels()),
         gfx::PNGCodec::FORMAT_BGRA,
         gfx::Size(image.width(), image.height()),
         static_cast<int>(image.rowBytes()),
         discard_transparency,
         comments,
@@ skipping 99 matching lines @@
   }
   base::MessageLoop::current()->RunUntilIdle();
 }
 
 void WebKitTestController::OnResetDone() {
   base::MessageLoop::current()->PostTask(FROM_HERE,
                                          base::MessageLoop::QuitClosure());
 }
 
 }  // namespace content