[Presentation API] Implement ondefaultsessionstart in PSImpl.

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 "base/callback.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/presentation_session.h"
 
 namespace content {
 
 class PresentationScreenAvailabilityListener;
 
 // An interface implemented by embedders to handle presentation API calls
 // forwarded from PresentationServiceImpl.
 class CONTENT_EXPORT PresentationServiceDelegate {
  public:
   // Observer interface to listen for changes to PresentationServiceDelegate.
   class CONTENT_EXPORT Observer {
    public:
     // Called when the PresentationServiceDelegate is being destroyed.
     virtual void OnDelegateDestroyed() = 0;
 
+    // Called when the default presentation has been started outside of a
+    // Presentation API context (e.g., browser action). This will not be called
+    // if the session was created as a result of Presentation API's
+    // StartSession()/JoinSession().
+    virtual void OnDefaultPresentationStarted(
+        const PresentationSessionInfo& session) = 0;
+
    protected:
     virtual ~Observer() {}
   };
 
   using PresentationSessionSuccessCallback =
       base::Callback<void(const PresentationSessionInfo&)>;
   using PresentationSessionErrorCallback =
       base::Callback<void(const PresentationError&)>;
 
   virtual ~PresentationServiceDelegate() {}
 
-  // Registers an observer with this class to listen for updates to this class.
+  // Registers an observer associated with frame with |render_process_id|
+  // and |render_frame_id| with this class to listen for updates.
   // This class does not own the observer.
-  // It is an error to add an observer if it has already been added before.
-  virtual void AddObserver(Observer* observer) = 0;
-  // Unregisters an observer with this class.
-  virtual void RemoveObserver(Observer* observer) = 0;
+  // It is an error to add an observer if there is already an observer for that
+  // frame.
+  virtual void AddObserver(int render_process_id,
+                           int render_frame_id,
+                           Observer* observer) = 0;
+
+  // Unregisters the observer associated with the frame with |render_process_id|
+  // and |render_frame_id|.
+  // The observer will no longer receive updates.
+  virtual void RemoveObserver(int render_process_id, int render_frame_id) = 0;
 
   // Registers |listener| to continuously listen for
   // availability updates for a presentation URL, originated from the frame
   // given by |render_process_id| and |render_frame_id|.
   // This class does not own |listener|.
   // Returns true on success.
   // This call will return false if a listener with the same presentation URL
   // from the same frame is already registered.
   virtual bool AddScreenAvailabilityListener(
       int render_process_id,
@@ skipping 60 matching lines @@
       int render_frame_id,
       const std::string& presentation_url,
       const std::string& presentation_id,
       const PresentationSessionSuccessCallback& success_cb,
       const PresentationSessionErrorCallback& error_cb) = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_PRESENTATION_SERVICE_DELEGATE_H_