Refactor the way singleton-style resources are exposed via PPB_Instance

ppapi/proxy/gamepad_resource.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 "ppapi/proxy/gamepad_resource.h"
 
 #include <string.h>
 
 #include "base/bind.h"
 #include "base/threading/platform_thread.h"
@@ skipping 40 matching lines @@
   SendCreate(BROWSER, PpapiHostMsg_Gamepad_Create());
   Call<PpapiPluginMsg_Gamepad_SendMemory>(
       BROWSER,
       PpapiHostMsg_Gamepad_RequestMemory(),
       base::Bind(&GamepadResource::OnPluginMsgSendMemory, this));
 }
 
 GamepadResource::~GamepadResource() {
 }
 
+thunk::PPB_Gamepad_API* GamepadResource::AsPPB_Gamepad_API() {
+  return this;
+}
+
 void GamepadResource::Sample(PP_GamepadsSampleData* data) {
   if (!buffer_) {
     // Browser hasn't sent back our shared memory, give the plugin gamepad
     // data corresponding to "not connected".
     memset(data, 0, sizeof(PP_GamepadsSampleData));
     return;
   }
 
   // ==========
   //   DANGER
@@ skipping 31 matching lines @@
   params.TakeSharedMemoryHandleAtIndex(0, &handle);
 
   shared_memory_.reset(new base::SharedMemory(handle, true));
   CHECK(shared_memory_->Map(sizeof(ContentGamepadHardwareBuffer)));
   buffer_ = static_cast<const ContentGamepadHardwareBuffer*>(
       shared_memory_->memory());
 }
 
 }  // namespace proxy
 }  // namespace ppapi