Add MessageLoopProxy::current

base/message_loop_proxy.h

 // Copyright (c) 2011 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 BASE_MESSAGE_LOOP_PROXY_H_
 #define BASE_MESSAGE_LOOP_PROXY_H_
 #pragma once
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/task.h"
 
 namespace base {
 
 struct MessageLoopProxyTraits;
 
 // This class provides a thread-safe refcounted interface to the Post* methods
-// of a message loop. This class can outlive the target message loop. You can
-// obtain a MessageLoopProxy via Thread::message_loop_proxy() or
-// MessageLoopProxy::CreateForCurrentThread().
+// of a message loop. This class can outlive the target message loop.
+// MessageLoopProxy objects are constructed automatically for all MessageLoops.
+// So, to access them, you can use any of the following:
+//   Thread::message_loop_proxy()
+//   MessageLoop::current()->message_loop_proxy()
+//   MessageLoopProxy::current()
 class BASE_EXPORT MessageLoopProxy
     : public base::RefCountedThreadSafe<MessageLoopProxy,
                                         MessageLoopProxyTraits> {
  public:
   // These methods are the same as in message_loop.h, but are guaranteed to
   // either post the Task to the MessageLoop (if it's still alive), or to
   // delete the Task otherwise.
   // They return true iff the thread existed and the task was posted.  Note that
   // even if the task is posted, there's no guarantee that it will run; for
   // example the target loop may already be quitting, or in the case of a
@@ skipping 38 matching lines @@
   bool DeleteSoon(const tracked_objects::Location& from_here,
                   T* object) {
     return PostNonNestableTask(from_here, new DeleteTask<T>(object));
   }
   template <class T>
   bool ReleaseSoon(const tracked_objects::Location& from_here,
                    T* object) {
     return PostNonNestableTask(from_here, new ReleaseTask<T>(object));
   }
 
-  // Factory method for creating an implementation of MessageLoopProxy
-  // for the current thread.
-  static scoped_refptr<MessageLoopProxy> CreateForCurrentThread();
+  // Gets the MessageLoopProxy for the current message loop, creating one if
+  // needed.
+  static scoped_refptr<MessageLoopProxy> current();
 
  protected:
   friend class RefCountedThreadSafe<MessageLoopProxy, MessageLoopProxyTraits>;
   friend struct MessageLoopProxyTraits;
 
   MessageLoopProxy();
   virtual ~MessageLoopProxy();
 
   // Called when the proxy is about to be deleted. Subclasses can override this
   // to provide deletion on specific threads.
   virtual void OnDestruct() const;
 };
 
 struct MessageLoopProxyTraits {
   static void Destruct(const MessageLoopProxy* proxy) {
     proxy->OnDestruct();
   }
 };
 
 }  // namespace base
 
 #endif  // BASE_MESSAGE_LOOP_PROXY_H_