Refactor the PlatformContext layer to have only one class.

chrome/renderer/webplugin_delegate_proxy.cc

 // Copyright (c) 2006-2008 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 "chrome/renderer/webplugin_delegate_proxy.h"
 
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <atlbase.h>
@@ skipping 414 matching lines @@
 
 bool WebPluginDelegateProxy::CreateBitmap(
     scoped_ptr<base::SharedMemory>* memory,
     scoped_ptr<skia::PlatformCanvas>* canvas) {
 #if defined(OS_WIN)
   size_t size = GetPaintBufSize(plugin_rect_);
   scoped_ptr<base::SharedMemory> new_shared_memory(new base::SharedMemory());
   if (!new_shared_memory->Create(L"", false, true, size))
     return false;
 
-  scoped_ptr<skia::PlatformCanvasWin> new_canvas(new skia::PlatformCanvasWin);
+  scoped_ptr<skia::PlatformCanvas> new_canvas(new skia::PlatformCanvas);
   if (!new_canvas->initialize(plugin_rect_.width(), plugin_rect_.height(),
                               true, new_shared_memory->handle())) {
     return false;
   }
 
   memory->swap(new_shared_memory);
   canvas->swap(new_canvas);
   return true;
 #else
   // TODO(port): use TransportDIB properly.
@@ skipping 463 matching lines @@
   plugin_->CancelDocumentLoad();
 }
 
 void WebPluginDelegateProxy::OnInitiateHTTPRangeRequest(
     const std::string& url, const std::string& range_info,
     intptr_t existing_stream, bool notify_needed, intptr_t notify_data) {
   plugin_->InitiateHTTPRangeRequest(url.c_str(), range_info.c_str(),
                                     existing_stream, notify_needed,
                                     notify_data);
 }