base: Mark MessageLoop::Post*Task API deprecated

base/message_loop/message_loop.h

Index: base/message_loop/message_loop.h
diff --git a/base/message_loop/message_loop.h b/base/message_loop/message_loop.h
index 7c76616f20f9123056c9d78dfcf1c964e752d017..4500340b158b4d02c1b5e7db2b717d75e27203b6 100644
--- a/base/message_loop/message_loop.h
+++ b/base/message_loop/message_loop.h
@@ -155,6 +155,8 @@ class BASE_EXPORT MessageLoop : public MessagePump::Delegate {
   // DestructionObserver is receiving a notification callback.
   void RemoveDestructionObserver(DestructionObserver* destruction_observer);
 
+  // NOTE: Deprecated; prefer task_runner() and the TaskRunner interfaces.
+  //
   // The "PostTask" family of methods call the task's Run method asynchronously
   // from within a message loop at some point in the future.
   //