Remove calls to MessageLoop::current() in chrome.

chrome/utility/image_writer/disk_unmounter_mac.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 "chrome/utility/image_writer/disk_unmounter_mac.h"
 
 #include <IOKit/storage/IOStorageProtocolCharacteristics.h>
 #include <sys/socket.h>
 
 #include "base/message_loop/message_pump_mac.h"
@@ skipping 75 matching lines @@
   disk_unmounter->original_thread_->PostTask(
       FROM_HERE, disk_unmounter->success_continuation_);
 }
 
 // static
 std::unique_ptr<base::MessagePump> DiskUnmounterMac::CreateMessagePump() {
   return std::unique_ptr<base::MessagePump>(new base::MessagePumpCFRunLoop);
 }
 
 void DiskUnmounterMac::UnmountOnWorker(const std::string& device_path) {
-  DCHECK(cf_thread_.message_loop() == base::MessageLoop::current());
+  DCHECK(cf_thread_.task_runner()->BelongsToCurrentThread());
 
   session_.reset(DASessionCreate(NULL));
 
   DASessionScheduleWithRunLoop(
       session_, CFRunLoopGetCurrent(), kCFRunLoopCommonModes);
 
   disk_.reset(DADiskCreateFromBSDName(
       kCFAllocatorDefault, session_, device_path.c_str()));
 
   if (!disk_) {
     LOG(ERROR) << "Unable to get disk reference.";
     Error();
     return;
   }
 
   DADiskClaim(disk_,
               kDADiskClaimOptionDefault,
               DiskClaimRevoked,
               this,
               DiskClaimed,
               this);
 }
 
 void DiskUnmounterMac::Error() {
   original_thread_->PostTask(FROM_HERE, failure_continuation_);
 }
 
 }  // namespace image_writer