[Presentation API] Additional plumbing for PresentationServiceImpl.

content/renderer/presentation/presentation_dispatcher.h

Index: content/renderer/presentation/presentation_dispatcher.h
diff --git a/content/renderer/presentation/presentation_dispatcher.h b/content/renderer/presentation/presentation_dispatcher.h
index e17d72ac0e6e24ac3ff340c2e841cab03c366860..2fcd493928ff5844998dc5e11e4e78d6df436038 100644
--- a/content/renderer/presentation/presentation_dispatcher.h
+++ b/content/renderer/presentation/presentation_dispatcher.h
@@ -45,16 +45,22 @@ class CONTENT_EXPORT PresentationDispatcher
   // RenderFrameObserver
   void DidChangeDefaultPresentation() override;
 
-  void OnScreenAvailabilityChanged(bool available);
+  void OnScreenAvailabilityChanged(
+      const std::string& presentation_url,
+      bool available);
   void OnSessionCreated(
-    blink::WebPresentationSessionClientCallbacks* callback,
-    presentation::PresentationSessionInfoPtr session_info,
-    presentation::PresentationErrorPtr error);
+      blink::WebPresentationSessionClientCallbacks* callback,
+      presentation::PresentationSessionInfoPtr session_info,
+      presentation::PresentationErrorPtr error);
   void OnDefaultSessionStarted(
       presentation::PresentationSessionInfoPtr session_info);
 
   void ConnectToPresentationServiceIfNeeded();
 
+  void DoUpdateAvailableChangeWatched(
+      const std::string& presentation_url,
+      bool watched);
+
   // Used as a weak reference. Can be null since lifetime is bound to the frame.
   blink::WebPresentationController* controller_;
   presentation::PresentationServicePtr presentation_service_;