Presentation API: startSession() no longer takes a presentation id.

public/platform/modules/presentation/WebPresentationClient.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 WebPresentationClient_h
 #define WebPresentationClient_h
 
 #include "public/platform/WebCallbacks.h"
 #include "public/platform/WebCommon.h"
 
@@ skipping 16 matching lines @@
 // The implementation the embedder has to provide for the Presentation API to work.
 class WebPresentationClient {
 public:
     virtual ~WebPresentationClient() { }
 
     // Passes the Blink-side delegate to the embedder.
     virtual void setController(WebPresentationController*) = 0;
 
     // Called when the frame requests to start a new session.
     // The ownership of the |callbacks| argument is transferred to the embedder.
-    virtual void startSession(const WebString& presentationUrl, const WebString& presentationId, WebPresentationSessionClientCallbacks*) = 0;
+    virtual void startSession(const WebString& presentationUrl, WebPresentationSessionClientCallbacks*) = 0;
 
     // Called when the frame requests to join an existing session.
     // The ownership of the |callbacks| argument is transferred to the embedder.
     virtual void joinSession(const WebString& presentationUrl, const WebString& presentationId, WebPresentationSessionClientCallbacks*) = 0;
 
     // Called when the frame requests to send String message to an existing session.
     virtual void sendString(const WebString& presentationUrl, const WebString& presentationId, const WebString& message) = 0;
 
     // Called when the frame requests to send ArrayBuffer/View data to an existing session.
     // Embedder copies the |data| and the ownership is not transferred.
@@ skipping 17 matching lines @@
     virtual void startListening(WebPresentationAvailabilityObserver*) = 0;
 
     // Stop listening to changes in presentation displays availability. The
     // observer will no longer be notified in case of a change.
     virtual void stopListening(WebPresentationAvailabilityObserver*) = 0;
 };
 
 } // namespace blink
 
 #endif // WebPresentationClient_h