[Presentation API] Plumbing the |defaultpresentationstart| event from Blink to browser/Mojo.

content/renderer/presentation/presentation_dispatcher.h

 // 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.
 
 #ifndef CONTENT_RENDERER_PRESENTATION_PRESENTATION_DISPATCHER_H_
 #define CONTENT_RENDERER_PRESENTATION_PRESENTATION_DISPATCHER_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_vector.h"
 #include "content/common/content_export.h"
@@ skipping 29 matching lines @@
   virtual void joinSession(
       const blink::WebString& presentationUrl,
       const blink::WebString& presentationId,
       blink::WebPresentationSessionClientCallbacks* callback);
 
   void OnScreenAvailabilityChanged(bool available);
   void OnSessionCreated(
     blink::WebPresentationSessionClientCallbacks* callback,
     presentation::PresentationSessionInfoPtr session_info,
     presentation::PresentationErrorPtr error);
+  void OnDefaultSessionStarted(
+      presentation::PresentationSessionInfoPtr session_info);
 
   void ConnectToPresentationServiceIfNeeded();
 
   // Used as a weak reference. Can be null since lifetime is bound to the frame.
   blink::WebPresentationController* controller_;
   presentation::PresentationServicePtr presentation_service_;
 
   // Wrappers around the PresentationSessionPtr corresponding to each Javascript
   // PresentationSession object passed back to the frame.
   // TODO(avayvod): Switch to base::IDMap when the lookup by presentation id is
   // needed.
   using PresentationSessionDispatchers =
       ScopedVector<PresentationSessionDispatcher>;
   PresentationSessionDispatchers presentation_session_dispatchers_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PRESENTATION_PRESENTATION_DISPATCHER_H_