Presentation API: implement .getAvailability() (Chromium side).

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 4642a644ba19899a626ce3a0db05f8e070d277cf..ca5ce6ddb97d2eb99113f8be2d9bf5189169c545 100644
--- a/content/renderer/presentation/presentation_dispatcher.h
+++ b/content/renderer/presentation/presentation_dispatcher.h
@@ -6,6 +6,7 @@
 #define CONTENT_RENDERER_PRESENTATION_PRESENTATION_DISPATCHER_H_
 
 #include "base/compiler_specific.h"
+#include "base/id_map.h"
 #include "base/memory/linked_ptr.h"
 #include "content/common/content_export.h"
 #include "content/common/presentation/presentation_service.mojom.h"
@@ -13,6 +14,7 @@
 #include "third_party/WebKit/public/platform/modules/presentation/WebPresentationClient.h"
 
 namespace blink {
+class WebPresentationAvailabilityObserver;
 class WebString;
 }  // namespace blink
 
@@ -58,6 +60,11 @@ class CONTENT_EXPORT PresentationDispatcher
   virtual void closeSession(
       const blink::WebString& presentationUrl,
       const blink::WebString& presentationId);
+  virtual void getAvailability(
+      const blink::WebString& presentationUrl,
+      blink::WebPresentationAvailabilityCallbacks* callbacks);
+  virtual void startListening(blink::WebPresentationAvailabilityObserver*);
+  virtual void stopListening(blink::WebPresentationAvailabilityObserver*);
 
   // RenderFrameObserver implementation.
   void DidChangeDefaultPresentation() override;
@@ -84,6 +91,8 @@ class CONTENT_EXPORT PresentationDispatcher
 
   void ConnectToPresentationServiceIfNeeded();
 
+  void UpdateListeningState();
+
   // Used as a weak reference. Can be null since lifetime is bound to the frame.
   blink::WebPresentationController* controller_;
   presentation::PresentationServicePtr presentation_service_;
@@ -95,6 +104,23 @@ class CONTENT_EXPORT PresentationDispatcher
       std::queue<linked_ptr<presentation::SessionMessage>>;
   MessageRequestQueue message_request_queue_;
 
+  enum class ListeningState {
+    Inactive,
+    Waiting,

[whywhat, 2015/07/02 22:42:48]

This state is not used, only to assign it to the listening_, but never checked.

[mlamouri (slow - plz ping), 2015/07/03 13:35:46]

It is not directly used but indirectly. When getAvailability() is called, if the
listening is WAITING, we will add the callback. If it is ACTIVE, we will resolve
it directly. It's different from INACTIVE because in that case, we should start
listening.

+    Active,
+  };
+
+  ListeningState listening_;

[whywhat, 2015/07/02 22:42:48]

s/listening_/listening_state_

[mlamouri (slow - plz ping), 2015/07/03 13:35:46]

Done.

+  bool previous_availability_;

[whywhat, 2015/07/02 22:42:48]

nit: previous to what? last_known_availability_ maybe?

[mlamouri (slow - plz ping), 2015/07/03 13:35:46]

Done.

+
+  using AvailabilityCallbacksMap =
+      IDMap<blink::WebPresentationAvailabilityCallbacks, IDMapOwnPointer>;
+  AvailabilityCallbacksMap availability_callbacks_;
+
+  using AvailabilityObserversSet =
+      std::set<blink::WebPresentationAvailabilityObserver*>;
+  AvailabilityObserversSet availability_observers_;
+
   DISALLOW_COPY_AND_ASSIGN(PresentationDispatcher);
 };