Pass Callback to TaskRunner by value and consume it on invocation (1)

content/browser/browser_thread_impl.h

 // 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.
 
 #ifndef CONTENT_BROWSER_BROWSER_THREAD_IMPL_H_
 #define CONTENT_BROWSER_BROWSER_THREAD_IMPL_H_
 
+#include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread.h"
+#include "base/time/time.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/browser_thread.h"
 
+namespace base {
+class MessageLoop;
+class RunLoop;
+}
+
+namespace tracked_objects {
+class Location;
+}
+
 namespace content {
 
 // Very few users should use this directly. To mock BrowserThreads, tests should
 // use TestBrowserThreadBundle instead.
 class CONTENT_EXPORT BrowserThreadImpl : public BrowserThread,
                                          public base::Thread {
  public:
   // Construct a BrowserThreadImpl with the supplied identifier.  It is an error
   // to construct a BrowserThreadImpl that already exists.
   explicit BrowserThreadImpl(BrowserThread::ID identifier);
@@ skipping 43 matching lines @@
   // The following are unique function names that makes it possible to tell
   // the thread id from the callstack alone in crash dumps.
   void UIThreadRun(base::RunLoop* run_loop);
   void DBThreadRun(base::RunLoop* run_loop);
   void FileThreadRun(base::RunLoop* run_loop);
   void FileUserBlockingThreadRun(base::RunLoop* run_loop);
   void ProcessLauncherThreadRun(base::RunLoop* run_loop);
   void CacheThreadRun(base::RunLoop* run_loop);
   void IOThreadRun(base::RunLoop* run_loop);
 
-  static bool PostTaskHelper(
-      BrowserThread::ID identifier,
-      const tracked_objects::Location& from_here,
-      const base::Closure& task,
-      base::TimeDelta delay,
-      bool nestable);
+  static bool PostTaskHelper(BrowserThread::ID identifier,
+                             const tracked_objects::Location& from_here,
+                             base::Closure task,
+                             base::TimeDelta delay,
+                             bool nestable);
 
   // Common initialization code for the constructors.
   void Initialize();
 
   // For testing.
   friend class ContentTestSuiteBaseListener;
   friend class TestBrowserThreadBundle;
   static void FlushThreadPoolHelperForTesting();
 
   // The identifier of this thread.  Only one thread can exist with a given
   // identifier at a given time.
   ID identifier_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BROWSER_THREAD_IMPL_H_