[MediaRouter] Update MR-2-Extension's PostMessage to return boolean.

chrome/browser/media/router/media_router.h

Index: chrome/browser/media/router/media_router.h
diff --git a/chrome/browser/media/router/media_router.h b/chrome/browser/media/router/media_router.h
index 0699d3f86bf8c26371cc08a93a19e59f515572da..269951b29ea5d2ed9b8a1195d76bb7dbc0af00ad 100644
--- a/chrome/browser/media/router/media_router.h
+++ b/chrome/browser/media/router/media_router.h
@@ -29,6 +29,8 @@ class MediaSinksObserver;
 using MediaRouteResponseCallback =
     base::Callback<void(scoped_ptr<MediaRoute>, const std::string&)>;
 
+using PostMessageCallback = base::Callback<void(bool sent)>;
+
 // An interface for handling resources related to media routing.
 // Responsible for registering observers for receiving sink availability
 // updates, handling route requests/responses, and operating on routes (e.g.
@@ -50,7 +52,8 @@ class MediaRouter {
   // TODO(imcheng): Support additional data types: Blob, ArrayBuffer,
   // ArrayBufferView.
   virtual void PostMessage(const MediaRoute::Id& route_id,

[mark a. foltz, 2015/06/11 05:04:29]

We should rename this SendMessage to be more consistent with send() in the
Presentation API.

[haibinlu, 2015/06/11 17:37:17]

Done.

-                           const std::string& message) = 0;
+                           const std::string& message,
+                           const PostMessageCallback& callback) = 0;
 
   // Clears the issue with the id |issue_id|.
   virtual void ClearIssue(const Issue::Id& issue_id) = 0;