Implement pepper flash fullscreen on Mac

ui/base/cocoa/fullscreen_window_manager.h

Index: ui/base/cocoa/fullscreen_window_manager.h
===================================================================
--- ui/base/cocoa/fullscreen_window_manager.h	(revision 0)
+++ ui/base/cocoa/fullscreen_window_manager.h	(revision 0)
@@ -0,0 +1,39 @@
+// 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.
+
+#ifndef UI_BASE_COCOA_FULLSCREEN_WINDOW_MANAGER_H_
+#define UI_BASE_COCOA_FULLSCREEN_WINDOW_MANAGER_H_
+#pragma once
+
+#import <Cocoa/Cocoa.h>
+
+#include "base/mac/mac_util.h"
+#include "base/memory/scoped_nsobject.h"
+
+// A utility class to manage the fullscreen mode for a given window. This class
+// also updates the window frame if the screen changes.
+@interface FullscreenWindowManager : NSObject {
+ @private
+  scoped_nsobject<NSWindow> window_;
+  // Explicitly keep track of the screen we want to position the window in.
+  // This is better than using -[NSWindow screen] because that might change if
+  // the screen changes to a low resolution.
+  scoped_nsobject<NSScreen> desiredScreen_;
+  base::mac::FullScreenMode fullscreenMode_;
+  BOOL fullscreenActive_;
+}
+
+- (id)initWithWindow:(NSWindow*)window
+       desiredScreen:(NSScreen*)desiredScreen;
+
+// Enables fullscreen mode which causes the menubar and dock to be hidden as
+// needed.
+- (void)enterFullscreenMode;
+
+// Exists fullscreen mode which stops hiding the menubar and dock.
+- (void)exitFullscreenMode;
+
+@end
+
+#endif  // UI_BASE_COCOA_FULLSCREEN_WINDOW_MANAGER_H_