Implement Device Orientation using shared memory in content/renderer.

content/renderer/device_orientation/device_motion_event_pump.h

 // Copyright 2013 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_RENDERER_DEVICE_MOTION_EVENT_PUMP_H_
 #define CONTENT_RENDERER_DEVICE_MOTION_EVENT_PUMP_H_
 
 #include "base/memory/scoped_ptr.h"
-#include "base/memory/shared_memory.h"
-#include "base/timer/timer.h"
-#include "content/public/renderer/render_process_observer.h"
+#include "content/renderer/device_orientation/device_sensor_event_pump.h"
 #include "content/renderer/shared_memory_seqlock_reader.h"
 #include "third_party/WebKit/public/platform/WebDeviceMotionData.h"
 
 namespace WebKit {
 class WebDeviceMotionListener;
 }
 
 namespace content {
-class RenderThread;
 
 typedef SharedMemorySeqLockReader<WebKit::WebDeviceMotionData>
     DeviceMotionSharedMemoryReader;
 
-class CONTENT_EXPORT DeviceMotionEventPump : public RenderProcessObserver {
+class CONTENT_EXPORT DeviceMotionEventPump : public DeviceSensorEventPump {
  public:
   DeviceMotionEventPump();
+  explicit DeviceMotionEventPump(int pump_delay_millis);
   virtual ~DeviceMotionEventPump();
 
-  static double GetDelayMillis();
-
   // Sets the listener to receive updates for device motion data at
-  // regular intervals.
-  // Returns true if the registration was successful.
-  bool SetListener(WebKit::WebDeviceMotionListener*);
-
-  void SetDeviceMotionReader(scoped_ptr<DeviceMotionSharedMemoryReader>);
-
-  void Attach(RenderThread* thread);
+  // regular intervals. Returns true if the registration was successful.
+  bool SetListener(WebKit::WebDeviceMotionListener* listener);
 
   // RenderProcessObserver implementation.
   virtual bool OnControlMessageReceived(const IPC::Message& message) OVERRIDE;
 
  protected:
-  // Delay between subsequent firing of events.
-  static const double kPumpDelayMillis;
-
-  // The pump is a tri-state automaton with allowed transitions as follows:
-  // STOPPED -> PENDING_START
-  // PENDING_START -> RUNNING
-  // PENDING_START -> STOPPED
-  // RUNNING -> STOPPED
-  enum PumpState {
-      STOPPED,
-      RUNNING,
-      PENDING_START
-  };
-
-  bool StartFetchingDeviceMotion();
-  bool StopFetchingDeviceMotion();
-  void OnDidStartDeviceMotion(base::SharedMemoryHandle renderer_handle);
-  void FireEvent();
+  virtual void FireEvent() OVERRIDE;
+  virtual bool InitializeReader(base::SharedMemoryHandle handle) OVERRIDE;
+  virtual bool SendStartMessage() OVERRIDE;
+  virtual bool SendStopMessage() OVERRIDE;
 
   WebKit::WebDeviceMotionListener* listener_;
   scoped_ptr<DeviceMotionSharedMemoryReader> reader_;
-  base::RepeatingTimer<DeviceMotionEventPump> timer_;
-  PumpState state_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_DEVICE_MOTION_EVENT_PUMP_H_