Add gamepad hardware data fetcher, and higher level thread container

content/browser/gamepad/gamepad_provider.h

+// 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.
+
+#ifndef CONTENT_BROWSER_GAMEPAD_PROVIDER_H_
+#define CONTENT_BROWSER_GAMEPAD_PROVIDER_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/message_loop_proxy.h"
+#include "base/shared_memory.h"
+#include "base/system_monitor/system_monitor.h"
+#include "base/task.h"
+#include "content/browser/gamepad/data_fetcher.h"
+#include "content/common/content_export.h"
+#include "content/common/gamepad_hardware_buffer.h"
+
+namespace base {
+class Thread;
+}
+
+struct GamepadMsg_Updated_Params;
+
+namespace gamepad {
+
+class CONTENT_EXPORT Provider :
+    public base::RefCountedThreadSafe<Provider>,
+    public base::SystemMonitor::DevicesChangedObserver {
+ public:
+  explicit Provider(DataFetcher* fetcher);
+
+  // Starts or Stops the provider. Called from creator_loop_.
+  void Start();
+  void Stop();
+  base::SharedMemoryHandle GetRendererSharedMemoryHandle(
+      base::ProcessHandle renderer_process);
+
+ private:
+  friend class base::RefCountedThreadSafe<Provider>;
+
+  virtual ~Provider();
+
+  // Method for starting the polling, runs on polling_thread_.
+  void DoInitializePollingThread();
+
+  // Method for polling a DataFetcher. Runs on the polling_thread_.
+  void DoPoll();
+  void ScheduleDoPoll();
+
+  virtual void OnDevicesChanged() OVERRIDE;
+
+  GamepadHardwareBuffer* SharedMemoryAsHardwareBuffer();
+
+  enum { kDesiredSamplingIntervalMs = 16 };
+
+  // The Message Loop on which this object was created.
+  // Typically the I/O loop, but may be something else during testing.
+  scoped_refptr<base::MessageLoopProxy> creator_loop_;
+  scoped_ptr<DataFetcher> provided_fetcher_;
+
+  // When polling_thread_ is running, members below are only to be used
+  // from that thread.
+  scoped_ptr<DataFetcher> data_fetcher_;
+  base::SharedMemory gamepad_shared_memory_;
+  bool devices_changed_;
+
+  // Polling is done on this background thread.
+  scoped_ptr<base::Thread> polling_thread_;
+
+  static Provider* instance_;
+  base::WeakPtrFactory<Provider> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(Provider);
+};
+
+}  // namespace gamepad
+
+#endif  // CONTENT_BROWSER_GAMEPAD_PROVIDER_H_