Add MessageLoop::QuitNow and use it to terminate a sync IPC....

base/message_loop.h

 // Copyright (c) 2006-2008 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 140 matching lines @@
   // messages.  This method may only be called on the same thread that called
   // Run, and Run must still be on the call stack.
   //
   // Use QuitTask if you need to Quit another thread's MessageLoop, but note
   // that doing so is fairly dangerous if the target thread makes nested calls
   // to MessageLoop::Run.  The problem being that you won't know which nested
   // run loop you are quiting, so be careful!
   //
   void Quit();
 
+  // This method is a variant of Quit, that does not wait for pending messages
+  // to be processed before returning from Run.
+  void QuitNow();
+
   // Invokes Quit on the current MessageLoop when run.  Useful to schedule an
   // arbitrary MessageLoop to Quit.
   class QuitTask : public Task {
    public:
     virtual void Run() {
       MessageLoop::current()->Quit();
     }
   };
 
   // A MessageLoop has a particular type, which indicates the set of
@@ skipping 360 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);
 
 #endif  // BASE_MESSAGE_LOOP_H_