[Presentation API] Additional plumbing for PresentationServiceImpl.

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 dd4ac02193db5457222ab8068a92d4177717385a..d86474fa6490350480ab6809e6536b13fa4ba2a5 100644
--- a/content/browser/presentation/presentation_service_impl.h
+++ b/content/browser/presentation/presentation_service_impl.h
@@ -11,6 +11,7 @@
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/linked_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "content/common/content_export.h"
 #include "content/common/presentation/presentation_service.mojom.h"
 #include "content/common/presentation/presentation_session.mojom.h"
@@ -56,7 +57,7 @@ class CONTENT_EXPORT PresentationServiceImpl
           presentation::PresentationErrorPtr)>;
 
   friend class PresentationServiceImplTest;
-  FRIEND_TEST_ALL_PREFIXES(PresentationServiceImplTest, RemoveAllListeners);
+  FRIEND_TEST_ALL_PREFIXES(PresentationServiceImplTest, Reset);
   FRIEND_TEST_ALL_PREFIXES(PresentationServiceImplTest,
       DidNavigateThisFrame);
   FRIEND_TEST_ALL_PREFIXES(PresentationServiceImplTest,
@@ -65,6 +66,12 @@ class CONTENT_EXPORT PresentationServiceImpl
       ThisRenderFrameDeleted);
   FRIEND_TEST_ALL_PREFIXES(PresentationServiceImplTest,
       NotThisRenderFrameDeleted);
+  FRIEND_TEST_ALL_PREFIXES(PresentationServiceImplTest,
+      SetDefaultPresentationUrl);
+  FRIEND_TEST_ALL_PREFIXES(PresentationServiceImplTest,
+      SetSameDefaultPresentationUrl);
+  FRIEND_TEST_ALL_PREFIXES(PresentationServiceImplTest,
+      ClearDefaultPresentationUrl);
 
   // |render_frame_host|: The RFH this instance is associated with.
   // |web_contents|: The WebContents to observe.
@@ -88,6 +95,8 @@ class CONTENT_EXPORT PresentationServiceImpl
       const mojo::String& presentation_url,
       const mojo::String& presentation_id,
       const NewSessionMojoCallback& callback) override;
+  void SetDefaultPresentationUrl(
+      const mojo::String& presentation_url) override;
 
   // mojo::InterfaceImpl override.
   // Note that this is called when the RenderFrameHost is deleted.
@@ -103,76 +112,18 @@ class CONTENT_EXPORT PresentationServiceImpl
   // PresentationServiceDelegate::Observer
   void OnDelegateDestroyed() override;
 
-  // Removes all listeners on this instance and informs the
-  // PresentationServiceDelegate of such.
-  void RemoveAllListeners();
-
-  RenderFrameHost* render_frame_host_;
-  PresentationServiceDelegate* delegate_;
-
-  // A helper data class used by PresentationServiceImpl to do bookkeeping
-  // of currently registered screen availability listeners.
-  // An instance of this class is a simple state machine that waits for both
-  // the available bit and the Mojo callback to become available.
-  // Once this happens, the Mojo callback will be invoked with the available
-  // bit, and the state machine will reset.
-  // The available bit is obtained from the embedder's media router.
-  // The callback is obtained from the renderer via PresentationServiceImpl's
-  // GetScreenAvailability().
-  class ScreenAvailabilityContext
-      : public PresentationScreenAvailabilityListener {
-   public:
-    explicit ScreenAvailabilityContext(
-        const std::string& presentation_url);
-    ~ScreenAvailabilityContext() override;
-
-    // If available bit exists, |callback| will be invoked with the bit and
-    // this state machine will reset.
-    // Otherwise |callback| is saved for later use.
-    // |callback|: Callback to the client of PresentationService
-    // (i.e. the renderer) that screen availability has changed, via Mojo.
-    void CallbackReceived(const ScreenAvailabilityMojoCallback& callback);
-
-    // Clears both callback and available bit.
-    void Reset();
-
-    // PresentationScreenAvailabilityListener implementation.
-    std::string GetPresentationUrl() const override;
-    // If callback exists, it will be invoked with |available| and
-    // this state machine will reset.
-    // Otherwise |available| is saved for later use.
-    // |available|: New screen availability for the presentation URL.
-    void OnScreenAvailabilityChanged(bool available) override;
-
-   private:
-    std::string presentation_url_;
-    scoped_ptr<ScreenAvailabilityMojoCallback> callback_ptr_;
-    scoped_ptr<bool> available_ptr_;
-  };
-
-  // Map from presentation URL to its ScreenAvailabilityContext state machine.
-  base::hash_map<std::string, linked_ptr<ScreenAvailabilityContext>>
-      availability_contexts_;
-
-  std::string default_presentation_url_;
+  // Sets |default_presentation_url_| to |presentation_url| and informs the
+  // delegate of such.
+  void DoSetDefaultPresentationUrl(const std::string& presentation_url);
 
-  // mojo::InterfaceImpl override.
-  // Note that this is called when the RenderFrameHost is deleted.
-  void OnConnectionError() override;
+  // Removes all listeners and resets default presentation URL on this instance
+  // and informs the PresentationServiceDelegate of such.
+  void Reset();
 
-  // WebContentsObserver override.
-  void DidNavigateAnyFrame(
-      content::RenderFrameHost* render_frame_host,
-      const content::LoadCommittedDetails& details,
-      const content::FrameNavigateParams& params) override;
-  void RenderFrameDeleted(content::RenderFrameHost* render_frame_host) override;
-
-  // PresentationServiceDelegate::Observer
-  void OnDelegateDestroyed() override;
-
-  // Removes all listeners on this instance and informs the
-  // PresentationServiceDelegate of such.
-  void RemoveAllListeners();
+  // Callbacks from the embedder as a result of StartSession/JoinSession.
+  void OnStartOrJoinSessionSucceeded(
+      const PresentationSessionInfo& session_info);
+  void OnStartOrJoinSessionError(const PresentationError& error);
 
   RenderFrameHost* render_frame_host_;
   PresentationServiceDelegate* delegate_;
@@ -211,6 +162,11 @@ class CONTENT_EXPORT PresentationServiceImpl
     // |available|: New screen availability for the presentation URL.
     void OnScreenAvailabilityChanged(bool available) override;
 
+    // Gets the callback as a raw pointer.
+    ScreenAvailabilityMojoCallback* callback() const {
+      return callback_ptr_.get();
+    }
+
    private:
     std::string presentation_url_;
     scoped_ptr<ScreenAvailabilityMojoCallback> callback_ptr_;
@@ -223,6 +179,16 @@ class CONTENT_EXPORT PresentationServiceImpl
 
   std::string default_presentation_url_;
 
+  // This is set when there is a StartSession/JoinSession in progress.
+  // Additional StartSession/JoinSession calls are ignored while this is

[whywhat, 2015/03/10 17:05:04]

Is this a temporary limitation? What if the frame wants to start two
presentations (possibly with two different URLs/IDs but possibly to use two
screens)?

[imcheng, 2015/03/10 18:31:15]

For StartSession, we can only process one at a time since it opens up a dialog
in Chrome. There's other ways to deal with additional StartSession calls while
one is already in progress though -- perhaps we should queue up the StartSession
requests instead of ignoring?


For JoinSession, I think it's possible to have multiple of these in progress. We
can use a map to keep track of join requests. We can use some generated key to
make sure we match up the callbacks with the requests correctly. WDYT?

+  // set.
+  // When embedder returns with a result, this callback will be invoked and then
+  // reset.
+  scoped_ptr<NewSessionMojoCallback> start_or_join_session_cb_;
+
+  // NOTE: Weak pointers must be invalidated before all other member variables.
+  base::WeakPtrFactory<PresentationServiceImpl> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(PresentationServiceImpl);
 };