Makes ViewManagerServiceImpl track a single root

mojo/services/view_manager/view_manager_service_impl.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_SERVICES_VIEW_MANAGER_VIEW_MANAGER_SERVICE_IMPL_H_
 #define MOJO_SERVICES_VIEW_MANAGER_VIEW_MANAGER_SERVICE_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 44 matching lines @@
   ConnectionSpecificId creator_id() const { return creator_id_; }
   const std::string& url() const { return url_; }
 
   // Returns the View with the specified id.
   ServerView* GetView(const ViewId& id) {
     return const_cast<ServerView*>(
         const_cast<const ViewManagerServiceImpl*>(this)->GetView(id));
   }
   const ServerView* GetView(const ViewId& id) const;
 
-  // Returns true if this has |id| as a root.
-  bool HasRoot(const ViewId& id) const;
-  const ViewIdSet& roots() const { return roots_; }
+  // Returns true if this connection's root is |id|.
+  bool IsRoot(const ViewId& id) const;
 
   // Invoked when a connection is about to be destroyed.
   void OnWillDestroyViewManagerServiceImpl(ViewManagerServiceImpl* connection);
 
   // The following methods are invoked after the corresponding change has been
   // processed. They do the appropriate bookkeeping and update the client as
   // necessary.
   void ProcessViewBoundsChanged(const ServerView* view,
                                 const gfx::Rect& old_bounds,
                                 const gfx::Rect& new_bounds,
@@ skipping 23 matching lines @@
   // TODO(sky): move this to private section (currently can't because of
   // bindings).
   // InterfaceImp overrides:
   void OnConnectionError() override;
 
  private:
   typedef std::map<ConnectionSpecificId, ServerView*> ViewMap;
 
   bool IsViewKnown(const ServerView* view) const;
 
-  // Returns true if this ViewManagerServiceImpl is providing a root for
-  // |connection|. That is, |connection| is embedded in one of our views. If
-  // this ViewManagerServiceImpl does provide a root, |root_id|
-  // is set to that root.
-  bool ProvidesRoot(const ViewManagerServiceImpl* connection,
-                    ViewId* root_id) const;
-
   // These functions return true if the corresponding mojom function is allowed
   // for this connection.
   bool CanReorderView(const ServerView* view,
                       const ServerView* relative_view,
                       OrderDirection direction) const;
 
   // Deletes a view owned by this connection. Returns true on success. |source|
   // is the connection that originated the change.
   bool DeleteViewImpl(ViewManagerServiceImpl* source, ServerView* view);
 
   // If |view| is known (in |known_views_|) does nothing. Otherwise adds |view|
   // to |views|, marks |view| as known and recurses.
   void GetUnknownViewsFrom(const ServerView* view,
                            std::vector<const ServerView*>* views);
 
   // Removes |view| and all its descendants from |known_views_|. This does not
   // recurse through views that were created by this connection. All views owned
   // by this connection are added to |local_views|.
   void RemoveFromKnown(const ServerView* view,
                        std::vector<ServerView*>* local_views);
 
-  // Removes |view_id| from the set of roots this connection knows about.
-  void RemoveRoot(const ViewId& view_id);
+  // Resets the root of this connection.
+  void RemoveRoot();
 
   void RemoveChildrenAsPartOfEmbed(const ViewId& view_id);
 
   // Converts View(s) to ViewData(s) for transport. This assumes all the views
   // are valid for the client. The parent of views the client is not allowed to
   // see are set to NULL (in the returned ViewData(s)).
   Array<ViewDataPtr> ViewsToViewDatas(
       const std::vector<const ServerView*>& views);
   ViewDataPtr ViewToViewData(const ServerView* view);
 
@@ skipping 40 matching lines @@
                        const Callback<void(bool)>& callback) override;
   void Embed(const String& url,
              Id view_id,
              ServiceProviderPtr service_provider,
              const Callback<void(bool)>& callback) override;
 
   // InterfaceImpl:
   void OnConnectionEstablished() override;
 
   // AccessPolicyDelegate:
-  const base::hash_set<Id>& GetRootsForAccessPolicy() const override;
+  bool IsRootForAccessPolicy(const ViewId& id) const override;
   bool IsViewKnownForAccessPolicy(const ServerView* view) const override;
   bool IsViewRootOfAnotherConnectionForAccessPolicy(
       const ServerView* view) const override;
 
   ConnectionManager* connection_manager_;
 
   // Id of this connection as assigned by ConnectionManager.
   const ConnectionSpecificId id_;
 
   // URL this connection was created for.
   const std::string url_;
 
   // ID of the connection that created us. If 0 it indicates either we were
   // created by the root, or the connection that created us has been destroyed.
   ConnectionSpecificId creator_id_;
 
   // The URL of the app that embedded the app this connection was created for.
   const std::string creator_url_;
 
   scoped_ptr<AccessPolicy> access_policy_;
 
   // The views and views created by this connection. This connection owns these
   // objects.
   ViewMap view_map_;
 
   // The set of views that has been communicated to the client.
   ViewIdSet known_views_;
 
-  // Set of root views from other connections. More specifically any time
-  // Embed() is invoked the id of the view is added to this set for the child
-  // connection. The connection Embed() was invoked on (the parent) doesn't
-  // directly track which connections are attached to which of its views. That
-  // information can be found by looking through the |roots_| of all
-  // connections.
-  ViewIdSet roots_;
+  // The root of this connection. This is a scoped_ptr to reinforce the
+  // connection may have no root. A connection has no root if either the root
+  // is destroyed or Embed() is invoked on the root.
+  scoped_ptr<ViewId> root_;
 
   InterfaceRequest<ServiceProvider> service_provider_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewManagerServiceImpl);
 };
 
 #if defined(OS_WIN)
 #pragma warning(pop)
 #endif
 
 }  // namespace service
 }  // namespace mojo
 
 #endif  // MOJO_SERVICES_VIEW_MANAGER_VIEW_MANAGER_SERVICE_IMPL_H_