Mojo: Allow dispatchers to attach PlatformHandles to the MessageInTransit on serialization.

mojo/system/message_pipe_dispatcher.h

Index: mojo/system/message_pipe_dispatcher.h
diff --git a/mojo/system/message_pipe_dispatcher.h b/mojo/system/message_pipe_dispatcher.h
index ab3067c57490928db4e87aa6ecfe3a9b23c308fc..9b1b3faa22ee051c95561b2a3a540d116438d4ee 100644
--- a/mojo/system/message_pipe_dispatcher.h
+++ b/mojo/system/message_pipe_dispatcher.h
@@ -76,11 +76,14 @@ class MOJO_SYSTEM_IMPL_EXPORT MessagePipeDispatcher : public Dispatcher {
                                          MojoWaitFlags flags,
                                          MojoResult wake_result) OVERRIDE;
   virtual void RemoveWaiterImplNoLock(Waiter* waiter) OVERRIDE;
-  virtual size_t GetMaximumSerializedSizeImplNoLock(
-      const Channel* channel) const OVERRIDE;
-  virtual bool SerializeAndCloseImplNoLock(Channel* channel,
-                                           void* destination,
-                                           size_t* actual_size) OVERRIDE;
+  virtual void StartSerializeImplNoLock(Channel* channel,
+                                        size_t* max_size,
+                                        size_t* max_platform_handles) OVERRIDE;
+  virtual bool EndSerializeAndCloseImplNoLock(
+      Channel* channel,
+      void* destination,
+      size_t* actual_size,
+      std::vector<embedder::PlatformHandle>* platform_handles) OVERRIDE;
 
   // Protected by |lock()|:
   scoped_refptr<MessagePipe> message_pipe_;  // This will be null if closed.