Move MessageLoop to base namespace.

base/message_loop.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 BASE_MESSAGE_LOOP_H_
 #define BASE_MESSAGE_LOOP_H_
 
 #include <queue>
 #include <string>
 
@@ skipping 24 matching lines @@
 #if defined(USE_AURA) && defined(USE_X11) && !defined(OS_NACL)
 #include "base/message_pump_aurax11.h"
 #else
 #include "base/message_pump_gtk.h"
 #endif
 
 #endif
 #endif
 
 namespace base {
+
 class HistogramBase;
 class RunLoop;
 class ThreadTaskRunnerHandle;
 #if defined(OS_ANDROID)
 class MessagePumpForUI;
 #endif
-}  // namespace base
 
 // A MessageLoop is used to process events for a particular thread.  There is
 // at most one MessageLoop instance per thread.
 //
 // Events include at a minimum Task instances submitted to PostTask and its
 // variants.  Depending on the type of message pump used by the MessageLoop
 // other events such as UI messages may be processed.  On Windows APC calls (as
 // time permits) and signals sent to a registered set of HANDLEs may also be
 // processed.
 //
@@ skipping 636 matching lines @@
   }
 #endif  // defined(OS_POSIX)
 };
 
 // Do not add any member variables to MessageLoopForIO!  This is important b/c
 // MessageLoopForIO is often allocated via MessageLoop(TYPE_IO).  Any extra
 // data that you need should be stored on the MessageLoop's pump_ instance.
 COMPILE_ASSERT(sizeof(MessageLoop) == sizeof(MessageLoopForIO),
                MessageLoopForIO_should_not_have_extra_member_variables);
 
+}  // namespace base
+
+// TODO(brettw) remove this when all users are updated to explicitly use the
+// namespace
+using base::MessageLoop;
+using base::MessageLoopForIO;
+using base::MessageLoopForUI;
+
 #endif  // BASE_MESSAGE_LOOP_H_