[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 bc1e0ef9ce9b8462f36fb0d688be76917e7e4509..fed1fe8ef0d12061f7410fe6fbd2c9cf15e701c4 100644
--- a/content/browser/presentation/presentation_service_impl.h
+++ b/content/browser/presentation/presentation_service_impl.h
@@ -5,12 +5,15 @@
 #ifndef CONTENT_BROWSER_PRESENTATION_PRESENTATION_SERVICE_IMPL_H_
 #define CONTENT_BROWSER_PRESENTATION_PRESENTATION_SERVICE_IMPL_H_
 
+#include <deque>
+
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/containers/hash_tables.h"
 #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"
@@ -50,15 +53,71 @@ class CONTENT_EXPORT PresentationServiceImpl
       mojo::InterfaceRequest<presentation::PresentationService> request);
 
  private:
-  using ScreenAvailabilityMojoCallback = mojo::Callback<void(bool)>;
+  using ScreenAvailabilityMojoCallback =
+      mojo::Callback<void(mojo::String, bool)>;
   using NewSessionMojoCallback =
       mojo::Callback<void(presentation::PresentationSessionInfoPtr,
           presentation::PresentationErrorPtr)>;
   using DefaultSessionMojoCallback =
       mojo::Callback<void(presentation::PresentationSessionInfoPtr)>;
 
+  // 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 CONTENT_EXPORT ScreenAvailabilityContext

[mark a. foltz, 2015/03/18 00:10:58]

Is CONTENT_EXPORT only for unit testing?

It is odd that this is a private class of PresentationServiceImpl yet is an
exported symbol.

[imcheng, 2015/03/18 00:56:53]

Yeah unfortunately this is needed otherwise unit tests won't link on component
builds.

+      : 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

[mark a. foltz, 2015/03/18 00:10:58]

Add a blank line before to help readability of the long docstring.

[imcheng, 2015/03/18 00:56:53]

Done.

+    // 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;
+
+    // Gets the callback as a raw pointer.
+    ScreenAvailabilityMojoCallback* GetCallback() const;
+
+   private:
+    std::string presentation_url_;
+    scoped_ptr<ScreenAvailabilityMojoCallback> callback_ptr_;
+    scoped_ptr<bool> available_ptr_;
+  };
+
+  // Context for a StartSession request.
+  struct CONTENT_EXPORT StartSessionRequest {

[mark a. foltz, 2015/03/18 00:10:58]

Similar comment about CONTENT_EXPORT.

[imcheng, 2015/03/18 00:56:53]

Ditto

+    StartSessionRequest(const std::string& presentation_url,
+                        const std::string& presentation_id,
+                        const NewSessionMojoCallback& callback);
+    ~StartSessionRequest();
+
+    const std::string presentation_url;
+    const std::string presentation_id;
+    const NewSessionMojoCallback callback;
+  };
+
   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,
@@ -67,6 +126,12 @@ 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.
@@ -111,58 +176,60 @@ class CONTENT_EXPORT PresentationServiceImpl
   // PresentationServiceDelegate::Observer
   void OnDelegateDestroyed() override;
 
-  // Removes all listeners on this instance and informs the
-  // PresentationServiceDelegate of such.
-  void RemoveAllListeners();
+  // Sets |default_presentation_url_| to |presentation_url| and informs the
+  // delegate of new default presentation URL and ID.
+  void DoSetDefaultPresentationUrl(
+      const std::string& presentation_url,
+      const std::string& presentation_id);
+
+  // Removes all listeners and resets default presentation URL on this instance
+  // and informs the PresentationServiceDelegate of such.
+  void Reset();
+
+  // Callbacks from the embedder as a result of StartSession/JoinSession.

[mark a. foltz, 2015/03/18 00:10:58]

I don't quite follow this comment - this is in content/browser so it is part of
Chrome (and depends on Mojo)? I don't think it can be a callback from a generic
embedder?

[imcheng, 2015/03/18 00:56:53]

I clarified the comments here.

What I mean is that these two functions from PSImpl (content code) are bound as
base::Callbacks and passed to the embedder via the PresentationServiceDelegate
interface to be invoked when the embedder knows whether session create/join
succeeded.

+  void OnStartOrJoinSessionSucceeded(
+      bool is_start_session,
+      const NewSessionMojoCallback& callback,
+      const PresentationSessionInfo& session_info);
+  void OnStartOrJoinSessionError(
+      bool is_start_session,
+      const NewSessionMojoCallback& callback,
+      const PresentationError& error);
+
+  // Requests delegate to start a session.
+  void DoStartSession(
+      const std::string& presentation_url,
+      const std::string& presentation_id,
+      const NewSessionMojoCallback& callback);
+
+  // Removes the head of the queue (which represents the request that has just
+  // been processed).
+  // Checks if there are any queued StartSession requests and if so, executes
+  // the first one in the queue.
+  void HandleQueuedStartSessionRequests();
+
+  // Gets the ScreenAvailabilityContext for |presentation_url|, or creates one
+  // if it does not exist.
+  ScreenAvailabilityContext* GetOrCreateAvailabilityContext(
+      const std::string& presentation_url);
 
   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_;
+  std::string default_presentation_id_;
+
+  // We only allow one StartSession request to be processed at a time.
+  // StartSession requests are queued here. When a request has been processed,
+  // it is removed from head of the queue.
+  std::deque<linked_ptr<StartSessionRequest>> queued_start_session_requests_;
+
+  // NOTE: Weak pointers must be invalidated before all other member variables.
+  base::WeakPtrFactory<PresentationServiceImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PresentationServiceImpl);
 };