Revert of Pass SequencedTaskRunner to PowerSaveBlocker for ui/file operations

content/browser/power_save_blocker_mac.cc

 // Copyright (c) 2012 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/power_save_blocker_impl.h"
 
 #include <IOKit/pwr_mgt/IOPMLib.h>
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
@@ skipping 79 matching lines @@
   DCHECK_EQ(base::PlatformThread::CurrentId(),
             g_power_thread.Pointer()->GetThreadId());
 
   if (assertion_ != kIOPMNullAssertionID) {
     IOReturn result = IOPMAssertionRelease(assertion_);
     LOG_IF(ERROR, result != kIOReturnSuccess)
         << "IOPMAssertionRelease: " << result;
   }
 }
 
-PowerSaveBlockerImpl::PowerSaveBlockerImpl(
-    PowerSaveBlockerType type,
-    Reason reason,
-    const std::string& description,
-    scoped_refptr<base::SequencedTaskRunner> ui_task_runner,
-    scoped_refptr<base::SequencedTaskRunner> blocking_task_runner)
-    : delegate_(new Delegate(type, description)),
-      ui_task_runner_(ui_task_runner),
-      blocking_task_runner_(blocking_task_runner) {
+PowerSaveBlockerImpl::PowerSaveBlockerImpl(PowerSaveBlockerType type,
+                                           Reason reason,
+                                           const std::string& description)
+    : delegate_(new Delegate(type, description)) {
   g_power_thread.Pointer()->message_loop()->PostTask(
       FROM_HERE,
       base::Bind(&Delegate::ApplyBlock, delegate_));
 }
 
 PowerSaveBlockerImpl::~PowerSaveBlockerImpl() {
   g_power_thread.Pointer()->message_loop()->PostTask(
       FROM_HERE,
       base::Bind(&Delegate::RemoveBlock, delegate_));
 }
 
 }  // namespace content