Don't send a value changed notification when a characteristic is written

device/bluetooth/bluetooth_remote_gatt_characteristic_mac.mm

 // Copyright 2016 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 "device/bluetooth/bluetooth_remote_gatt_characteristic_mac.h"
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ skipping 298 matching lines @@
   characteristic_value_read_or_write_in_progress_ = false;
   if (error) {
     VLOG(1) << "Bluetooth error while writing for characteristic, domain: "
             << base::SysNSStringToUTF8(error.domain)
             << ", error code: " << error.code;
     BluetoothGattService::GattErrorCode error_code =
         BluetoothDeviceMac::GetGattErrorCodeFromNSError(error);
     callbacks.second.Run(error_code);
     return;
   }
-  NSData* nsdata_value = cb_characteristic_.get().value;
-  const uint8_t* buffer = static_cast<const uint8_t*>(nsdata_value.bytes);
-  std::vector<uint8_t> gatt_value(buffer, buffer + nsdata_value.length);
   gatt_service_->GetMacAdapter()->NotifyGattCharacteristicValueChanged(this,
                                                                        value_);
   callbacks.first.Run();
 }
 
 void BluetoothRemoteGattCharacteristicMac::DidUpdateNotificationState(
     NSError* error) {
   std::vector<std::pair<NotifySessionCallback, ErrorCallback>>
       reentrant_safe_callbacks;
   reentrant_safe_callbacks.swap(start_notify_session_callbacks_);
@@ skipping 38 matching lines @@
   return (GetProperties() & BluetoothGattCharacteristic::PROPERTY_WRITE)
              ? CBCharacteristicWriteWithResponse
              : CBCharacteristicWriteWithoutResponse;
 }
 
 CBCharacteristic* BluetoothRemoteGattCharacteristicMac::GetCBCharacteristic()
     const {
   return cb_characteristic_.get();
 }
 }  // namespace device.