Presentation API: ignore presentation id passed to startSession().

content/public/browser/presentation_service_delegate.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_PUBLIC_BROWSER_PRESENTATION_SERVICE_DELEGATE_H_
 #define CONTENT_PUBLIC_BROWSER_PRESENTATION_SERVICE_DELEGATE_H_
 
 #include <vector>
 
 #include "base/callback.h"
@@ skipping 83 matching lines @@
   // Sets the default presentation URL and ID for frame given by
   // |render_process_id| and |render_frame_id|.
   // If |default_presentation_url| is empty, the default presentation URL will
   // be cleared.
   virtual void SetDefaultPresentationUrl(
       int render_process_id,
       int render_frame_id,
       const std::string& default_presentation_url,
       const std::string& default_presentation_id) = 0;
 
-  // Starts a new presentation session.
+  // Starts a new presentation session. The presentation id of the session will
+  // be the default presentation ID if any or a generated one otherwise.
   // Typically, the embedder will allow the user to select a screen to show
   // |presentation_url|.
   // |render_process_id|, |render_frame_id|: ID of originating frame.
   // |presentation_url|: URL of the presentation.
-  // |presentation_id|: The caller may provide an non-empty string to be used
-  // as the ID of the presentation. If empty, the default presentation ID
-  // will be used. If both are empty, the embedder will automatically generate
-  // one.
   // |success_cb|: Invoked with session info, if presentation session started
   // successfully.
   // |error_cb|: Invoked with error reason, if presentation session did not
   // start.
   virtual void StartSession(
       int render_process_id,
       int render_frame_id,
       const std::string& presentation_url,
-      const std::string& presentation_id,
       const PresentationSessionSuccessCallback& success_cb,
       const PresentationSessionErrorCallback& error_cb) = 0;
 
   // Joins an existing presentation session. Unlike StartSession(), this
   // does not bring a screen list UI.
   // |render_process_id|, |render_frame_id|: ID for originating frame.
   // |presentation_url|: URL of the presentation.
   // |presentation_id|: The ID of the presentation to join.
   // |success_cb|: Invoked with session info, if presentation session joined
   // successfully.
@@ skipping 29 matching lines @@
   virtual void SendMessage(
       int render_process_id,
       int render_frame_id,
       scoped_ptr<PresentationSessionMessage> message_request,
       const SendMessageCallback& send_message_cb) = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_PRESENTATION_SERVICE_DELEGATE_H_