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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CONTENT_RENDERER_DEVICE_ORIENTATION_EVENT_PUMP_H_
      6 #define CONTENT_RENDERER_DEVICE_ORIENTATION_EVENT_PUMP_H_
      7 
      8 #include "base/memory/scoped_ptr.h"
      9 #include "content/renderer/device_orientation/device_sensor_event_pump.h"
     10 #include "content/renderer/shared_memory_seqlock_reader.h"
     11 #include "third_party/WebKit/public/platform/WebDeviceOrientationData.h"
     12 
     13 namespace WebKit {
     14 class WebDeviceOrientationListener;
     15 }
     16 
     17 namespace content {
     18 
     19 typedef SharedMemorySeqLockReader<WebKit::WebDeviceOrientationData>
     20     DeviceOrientationSharedMemoryReader;
     21 
     22 class CONTENT_EXPORT DeviceOrientationEventPump : public DeviceSensorEventPump {
     23  public:
     24   // Angle threshold beyond which two orientation events are considered
     25   // sufficiently different.
     26   static const double kOrientationThreshold;
     27 
     28   DeviceOrientationEventPump();
     29   explicit DeviceOrientationEventPump(int pump_delay_millis);
     30   virtual ~DeviceOrientationEventPump();
     31 
     32   // Sets the listener to receive updates for device orientation data at
     33   // regular intervals. Returns true if the registration was successful.
     34   bool SetListener(WebKit::WebDeviceOrientationListener* listener);
     35 
     36   // RenderProcessObserver implementation.
     37   virtual bool OnControlMessageReceived(const IPC::Message& message) OVERRIDE;
     38 
     39  protected:
     40   virtual void FireEvent() OVERRIDE;
     41   virtual bool InitializeReader(base::SharedMemoryHandle handle) OVERRIDE;
     42   virtual bool SendStartMessage() OVERRIDE;
     43   virtual bool SendStopMessage() OVERRIDE;
     44 
     45   bool ShouldFireEvent(const WebKit::WebDeviceOrientationData& data) const;
     46 
     47   WebKit::WebDeviceOrientationListener* listener_;
     48   WebKit::WebDeviceOrientationData data_;
     49   scoped_ptr<DeviceOrientationSharedMemoryReader> reader_;
     50 };
     51 
     52 }  // namespace content
     53 
     54 #endif  // CONTENT_RENDERER_DEVICE_ORIENTATION_EVENT_PUMP_H_
     55