[Presentation API] (MR side) 1-UA: notify receiver page when receiver connection becomes available

content/browser/presentation/presentation_service_impl.h

Index: content/browser/presentation/presentation_service_impl.h
diff --git a/content/browser/presentation/presentation_service_impl.h b/content/browser/presentation/presentation_service_impl.h
index dea2c88c37d89940f495810411836156aac20d6c..292bbff20361be3b15ca8077229c5f42c593fc8c 100644
--- a/content/browser/presentation/presentation_service_impl.h
+++ b/content/browser/presentation/presentation_service_impl.h
@@ -48,7 +48,8 @@ class RenderFrameHost;
 class CONTENT_EXPORT PresentationServiceImpl
     : public NON_EXPORTED_BASE(blink::mojom::PresentationService),
       public WebContentsObserver,
-      public PresentationServiceDelegate::Observer {
+      public PresentationServiceDelegate::Observer,
+      public OffscreenPresentationClient {
  public:
   using NewSessionCallback =
       base::Callback<void(blink::mojom::PresentationSessionInfoPtr,
@@ -234,6 +235,15 @@ class CONTENT_EXPORT PresentationServiceImpl
       const ScopedVector<PresentationSessionMessage>& messages,
       bool pass_ownership);
 
+  // OffscreenPresentationClient Implementation
+  void OnReceiverConnectionAvailable(
+      const content::PresentationSessionInfo&) override;
+
+  void AddOffscreenPresentationObserver(OffscreenPresentationClient*) override;
+
+  void RemoveOffscreenPresentationObserver(
+      OffscreenPresentationClient*) override;
+
   // Associates a JoinSession |callback| with a unique request ID and
   // stores it in a map.
   // Returns a positive value on success.
@@ -284,6 +294,11 @@ class CONTENT_EXPORT PresentationServiceImpl
   int render_process_id_;
   int render_frame_id_;
 
+  // Offscreen presentation observer list for current frame.
+  // For controller PSImpl, it contains corresponding receiver PSImpl,
+  // and vise versa.
+  std::set<OffscreenPresentationClient*> offscreen_presentation_observers_;
+
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<PresentationServiceImpl> weak_factory_;