Gamepad API support for chrome on android

content/renderer/gamepad_shared_memory_reader.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2014, NVIDIA CORPORATION. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_GAMEPAD_SHARED_MEMORY_READER_H_
 #define CONTENT_RENDERER_GAMEPAD_SHARED_MEMORY_READER_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/shared_memory.h"
 #include "third_party/WebKit/public/platform/WebGamepads.h"
 
 namespace content {
 
 struct GamepadHardwareBuffer;
 
 class GamepadSharedMemoryReader {
  public:
   GamepadSharedMemoryReader();
   virtual ~GamepadSharedMemoryReader();
+#if defined(OS_ANDROID)
+  void ResumeGamepads();

[scottmg, 2014/01/13 19:42:43]

Could you explain why the renderer is calling these? What if a renderer crashes
and the Pause/Resumes become unbalanced?

[SaurabhK, 2014/01/15 16:57:08]

According to my observation polling thread which gets started in the constructor
of GamepadSharedMemoryReader never stops (even if i switch/close the tab that
accesses gamepad data or minimize the browser application).
In my implementation I want to resume and pause polling thread whenever gamepad
data is accessed and released. And I make sure the state of polling thread in
NavigatorGamepad's constructor and destructor. Hence these calls are from
NavigatorGamepad.
Also i am keeping a timeout in GamepadProvider which will put polling thread to
pause state whenever gamepad access stops.

SO coming back to the question of renderer crash, there can be two states
(resume/pause) of renderer at time of crash.
1. Paused
In this case whenever new webpage is loaded that accesses gamepad data,
NavigatorGamepad will make sure that the thread has resumed.

2. Resumed
In this case the timeout in GamepadProvider will put the polling thread to pause
as the gamepad access has been stopped.

+  void PauseGamepads();
+#endif
   void SampleGamepads(blink::WebGamepads&);
 
  private:
   base::SharedMemoryHandle renderer_shared_memory_handle_;
   scoped_ptr<base::SharedMemory> renderer_shared_memory_;
   GamepadHardwareBuffer* gamepad_hardware_buffer_;
 
   bool ever_interacted_with_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_GAMEPAD_SHARED_MEMORY_READER_H_