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diff --git a/chromium/content/browser/device_sensors/data_fetcher_shared_memory_base.h b/chromium/content/browser/device_sensors/data_fetcher_shared_memory_base.h
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+++ b/chromium/content/browser/device_sensors/data_fetcher_shared_memory_base.h
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+// Copyright 2014 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_DEVICE_SENSORS_DATA_FETCHER_SHARED_MEMORY_BASE_H_
+#define CONTENT_BROWSER_DEVICE_SENSORS_DATA_FETCHER_SHARED_MEMORY_BASE_H_
+
+#include <map>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/shared_memory.h"
+#include "base/message_loop/message_loop.h"
+#include "content/browser/device_sensors/inertial_sensor_consts.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+// Sensor data fetchers should derive from this base class and implement
+// the abstract Start() and Stop() methods.
+// If the fetcher requires polling it should also implement IsPolling()
+// to return true and the Fetch() method which will be called from the
+// polling thread to fetch data at regular intervals.
+class CONTENT_EXPORT DataFetcherSharedMemoryBase {
+ public:
+  // Starts updating the shared memory buffer with sensor data at
+  // regular intervals. Returns true if the relevant sensors could
+  // be successfully activated.
+  bool StartFetchingDeviceData(ConsumerType consumer_type);
+
+  // Stops updating the shared memory buffer. Returns true if the
+  // relevant sensors could be successfully deactivated.
+  bool StopFetchingDeviceData(ConsumerType consumer_type);
+
+  // Returns the shared memory handle of the device sensor data
+  // duplicated into the given process. This method should only be
+  // called after a call to StartFetchingDeviceData method with
+  // corresponding |consumer_type| parameter.
+  base::SharedMemoryHandle GetSharedMemoryHandleForProcess(
+      ConsumerType consumer_type, base::ProcessHandle process);
+
+  enum FetcherType {
+    // Fetcher runs on the same thread as its creator.
+    FETCHER_TYPE_DEFAULT,
+    // Fetcher runs on a separate thread calling |Fetch()| at regular intervals.
+    FETCHER_TYPE_POLLING_CALLBACK,
+    // Fetcher runs on a separate thread, but no callbacks are executed.
+    FETCHER_TYPE_SEPARATE_THREAD
+  };
+
+ protected:
+  class PollingThread;
+
+  DataFetcherSharedMemoryBase();
+  virtual ~DataFetcherSharedMemoryBase();
+
+  // Returns the message loop of the polling thread.
+  // Returns NULL if there is no polling thread.
+  base::MessageLoop* GetPollingMessageLoop() const;
+
+  // If IsPolling() is true this method is called from the |polling_thread_|
+  // at regular intervals.
+  virtual void Fetch(unsigned consumer_bitmask);
+
+  // Returns the type of thread this fetcher runs on.
+  virtual FetcherType GetType() const;
+
+  // Returns the sensor sampling interval. In particular if this fetcher
+  // GetType() == FETCHER_TYPE_POLLING_CALLBACK the interval between
+  // successive calls to Fetch().
+  virtual base::TimeDelta GetInterval() const;
+
+  // Start() method should call InitSharedMemoryBuffer() to get the shared
+  // memory pointer. If IsPolling() is true both Start() and Stop() methods
+  // are called from the |polling_thread_|.
+  virtual bool Start(ConsumerType consumer_type, void* buffer) = 0;
+  virtual bool Stop(ConsumerType consumer_type) = 0;
+
+  bool IsPollingTimerRunningForTesting() const;
+
+ private:
+  bool InitAndStartPollingThreadIfNecessary();
+  base::SharedMemory* GetSharedMemory(ConsumerType consumer_type);
+  void* GetSharedMemoryBuffer(ConsumerType consumer_type);
+
+  unsigned started_consumers_;
+
+  scoped_ptr<PollingThread> polling_thread_;
+
+  // Owning pointers. Objects in the map are deleted in dtor.
+  typedef std::map<ConsumerType, base::SharedMemory*> SharedMemoryMap;
+  SharedMemoryMap shared_memory_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(DataFetcherSharedMemoryBase);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_DEVICE_SENSORS_DATA_FETCHER_SHARED_MEMORY_BASE_H_