Fix "unused variable" warnings.

content/browser/device_sensors/data_fetcher_shared_memory_win.cc

 // 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.
 
 #include "content/browser/device_sensors/data_fetcher_shared_memory.h"
 
 #include <GuidDef.h>
 #include <InitGuid.h>
 #include <PortableDeviceTypes.h>
 #include <Sensors.h>
@@ skipping 242 matching lines @@
 
     return true;
   }
 
  private:
   DeviceLightHardwareBuffer* const buffer_;
 
   DISALLOW_COPY_AND_ASSIGN(SensorEventSinkLight);
 };
 
-DataFetcherSharedMemory::DataFetcherSharedMemory()
-    : motion_buffer_(nullptr),
-      orientation_buffer_(nullptr),
-      orientation_absolute_buffer_(nullptr),
-      light_buffer_(nullptr) {
-}
+DataFetcherSharedMemory::DataFetcherSharedMemory() {}
 
 DataFetcherSharedMemory::~DataFetcherSharedMemory() {
 }
 
 DataFetcherSharedMemory::FetcherType DataFetcherSharedMemory::GetType() const {
   return FETCHER_TYPE_SEPARATE_THREAD;
 }
 
 bool DataFetcherSharedMemory::Start(ConsumerType consumer_type, void* buffer) {
   DCHECK(buffer);
@@ skipping 214 matching lines @@
         motion_buffer_->data.allAvailableSensorsAreActive = enabled;
         motion_buffer_->seqlock.WriteEnd();
       }
       break;
     default:
       NOTREACHED();
   }
 }
 
 }  // namespace content