aura: Use PlatformWindow from WindowTreeHost.

ui/ozone/demo/egl_demo.cc

 // Copyright 2014 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/message_loop/message_loop.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_context.h"
@@ skipping 30 matching lines @@
   virtual void OnCloseRequest() OVERRIDE {}
   virtual void OnClosed() OVERRIDE {}
   virtual void OnWindowStateChanged(
       ui::PlatformWindowState new_state) OVERRIDE {}
   virtual void OnLostCapture() OVERRIDE {}
   virtual void OnAcceleratedWidgetAvailable(
       gfx::AcceleratedWidget widget) OVERRIDE {
     CHECK_NE(widget, gfx::kNullAcceleratedWidget);
     widget_ = widget;
   }
+  virtual void OnActivationChanged(bool active) OVERRIDE {}
 
  private:
   scoped_ptr<ui::PlatformWindow> platform_window_;
   gfx::AcceleratedWidget widget_;
 
   DISALLOW_COPY_AND_ASSIGN(DemoWindow);
 };
 
 int main(int argc, char** argv) {
   CommandLine::Init(argc, argv);
@@ skipping 30 matching lines @@
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
     float fraction = static_cast<float>(i) / iterations;
     glClearColor(1 - fraction, fraction, 0.0, 1.0);
 
     if (!surface->SwapBuffers())
       LOG(FATAL) << "Failed to swap buffers";
   }
 
   return 0;
 }