Fix the indirect pure virtual calls in DataFetcherSharedMemoryBase destructor.

content/browser/device_sensors/data_fetcher_shared_memory_base.h

 // 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"
@@ skipping 13 matching lines @@
  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);
 
+  // Should be called before destruction to make sure all active
+  // sensors are unregistered.
+  void StopFetchingAllDeviceData();
+
   // 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,
@@ skipping 45 matching lines @@
   // 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_