Allow CanvasSkia to bind to an existing SkCanvas.

ui/aura/window_unittest.cc

 // Copyright (c) 2011 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/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/message_loop.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/aura/desktop.h"
 #include "ui/aura/event.h"
@@ skipping 144 matching lines @@
 
   // Overridden from WindowDelegateImpl:
   virtual bool OnKeyEvent(KeyEvent* event) OVERRIDE {
     last_key_code_ = event->key_code();
     return true;
   }
   virtual void OnWindowDestroyed() OVERRIDE {
     delete this;
   }
   virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE {
-    canvas->AsCanvasSkia()->drawColor(color_, SkXfermode::kSrc_Mode);
+    canvas->GetSkCanvas()->drawColor(color_, SkXfermode::kSrc_Mode);
   }
 
  private:
   SkColor color_;
   ui::KeyboardCode last_key_code_;
 
   DISALLOW_COPY_AND_ASSIGN(TestWindowDelegate);
 };
 
 class WindowTest : public testing::Test {
@@ skipping 439 matching lines @@
   EXPECT_EQ(w11.get(), w1->GetEventHandlerForPoint(gfx::Point(10, 10)));
 
   w12->AddChild(w121.get());
 
   EXPECT_EQ(NULL, w1->GetEventHandlerForPoint(gfx::Point(10, 10)));
   EXPECT_EQ(w121.get(), w1->GetEventHandlerForPoint(gfx::Point(175, 175)));
 }
 
 }  // namespace internal
 }  // namespace aura