[PresentationAPI] Implementing send() from WebPresentationClient to the PresentationService.

content/common/presentation/presentation_service.mojom

 // Copyright 2015 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.
 
 module presentation;
 
 struct PresentationSessionInfo {
     string url;
     string id;
 };
@@ skipping 56 matching lines @@
     StartSession(string presentation_url, string? presentation_id)
         => (PresentationSessionInfo? sessionInfo, PresentationError? error);
 
     // Called when joinSession() is called by the frame. The result callback
     // works the same as for the method above. JoinSession will join a known
     // session (i.e. when the page navigates or the user opens another tab)
     // silently and without user action.
     JoinSession(string presentation_url, string? presentation_id)
         => (PresentationSessionInfo? sessionInfo, PresentationError? error);
 
+    // Called when send(String) is called by the frame. The result callback is to get

[mark a. foltz, 2015/04/10 19:03:18]

Please wrap at 80 columns.

[USE s.singapati at gmail.com, 2015/04/14 17:51:51]

Done.

+    // notified that message has been received and ready for the next one.
+    SendStringMessage(
+        string presentation_url,
+        string presentation_id,
+        string message) => ();
+
     // Called when closeSession() is called by the frame.
     CloseSession(string presentation_url, string presentation_id);
 
     // Called when the frame is ready to process the next state change. Returns
     // the last session state if it’s changed since the last time the callback
     // was called. Might cause the event fired with the initial state change.
     ListenForSessionStateChange()
         => (PresentationSessionInfo sessionInfo,
             PresentationSessionState newState);
 };