Introduce task_runner() accessors for both base::Thread and base::MessageLoop

base/threading/thread.h

Index: base/threading/thread.h
diff --git a/base/threading/thread.h b/base/threading/thread.h
index 9d446dd7feb01a3e9b23c5cd9c369890df05cd85..6f0dabcf8d0adf5159e9370c82574c7d74927ccc 100644
--- a/base/threading/thread.h
+++ b/base/threading/thread.h
@@ -143,10 +143,22 @@ class BASE_EXPORT Thread : PlatformThread::Delegate {
   // non-NULL after a successful call to Start. After Stop has been called,
   // this will return NULL. Callers can hold on to this even after the thread
   // is gone.
+  //
+  // Note: This method is deprecated. Callers should call task_runner() instead
+  // and use the TaskRunner interfaces for safely interfacing with the Thread.
   scoped_refptr<MessageLoopProxy> message_loop_proxy() const {
     return message_loop_ ? message_loop_->message_loop_proxy() : NULL;
   }
 
+  // Returns a TaskRunner for this thread. Use the TaskRunner's PostTask
+  // methods to execute code on the thread. This only returns non-NULL after

[awong, 2014/07/11 20:23:18]

How about "Returns NULL if thread is not running?

+  // a successfull call to Start. After Stop has been called, this will
+  // return NULL. Callers can hold on to this even after the thread is gone;
+  // in this situation, attempts to PostTask() will fail.
+  scoped_refptr<SingleThreadTaskRunner> task_runner() const {
+    return message_loop_proxy();
+  }
+
   // Returns the name of this thread (for display in debugger too).
   const std::string& thread_name() const { return name_; }