ui/gfx: Make gfx::Canvas inherit from gfx::CanvasSkia.

ui/aura/demo/demo_main.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 "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/i18n/icu_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "third_party/skia/include/core/SkXfermode.h"
 #include "ui/aura/event.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/base/hit_test.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/aura/root_window.h"
 #include "ui/base/ui_base_paths.h"
-#include "ui/gfx/canvas_skia.h"
+#include "ui/gfx/canvas.h"
 #include "ui/gfx/compositor/test/compositor_test_support.h"
 #include "ui/gfx/rect.h"
 
 #if defined(USE_X11)
 #include "base/message_pump_x.h"
 #endif
 
 namespace {
 
 // Trivial WindowDelegate implementation that draws a colored background.
@@ skipping 86 matching lines @@
   window3.Show();
   window3.SetParent(&window2);
 
   root_window->ShowRootWindow();
   MessageLoopForUI::current()->Run();
 
   ui::CompositorTestSupport::Terminate();
 
   return 0;
 }