re-use WebUIs

content/browser/web_contents/render_view_host_manager.h

 // Copyright (c) 2012 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 CONTENT_BROWSER_WEB_CONTENTS_RENDER_VIEW_HOST_MANAGER_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_RENDER_VIEW_HOST_MANAGER_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "content/browser/site_instance_impl.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/render_view_host_delegate.h"
 
 class InterstitialPageImpl;
 class NavigationControllerImpl;
 class WebUIImpl;
 
@@ skipping 95 matching lines @@
   // there is no current one.
   content::RenderWidgetHostView* GetRenderWidgetHostView() const;
 
   // Returns the pending render view host, or NULL if there is no pending one.
   content::RenderViewHostImpl* pending_render_view_host() const;
 
   // Returns the current committed Web UI or NULL if none applies.
   WebUIImpl* web_ui() const { return web_ui_.get(); }
 
   // Returns the Web UI for the pending navigation, or NULL of none applies.
-  WebUIImpl* pending_web_ui() const { return pending_web_ui_.get(); }
+  WebUIImpl* pending_web_ui() const {
+    return pending_web_ui_.get() ? pending_web_ui_.get() :
+                                   pending_and_current_web_ui_.get();
+  }
 
   // Called when we want to instruct the renderer to navigate to the given
   // navigation entry. It may create a new RenderViewHost or re-use an existing
   // one. The RenderViewHost to navigate will be returned. Returns NULL if one
   // could not be created.
   content::RenderViewHostImpl* Navigate(
       const content::NavigationEntryImpl& entry);
 
   // Instructs the various live views to stop. Called when the user directed the
   // page to stop loading.
@@ skipping 71 matching lines @@
   // switch.  Can be overridden in unit tests.
   bool ShouldTransitionCrossSite();
 
   // Returns true if the two navigation entries are incompatible in some way
   // other than site instances. Cases where this can happen include Web UI
   // to regular web pages. It will cause us to swap RenderViewHosts (and hence
   // RenderProcessHosts) even if the site instance would otherwise be the same.
   // As part of this, we'll also force new SiteInstances and BrowsingInstances.
   // Either of the entries may be NULL.
   bool ShouldSwapProcessesForNavigation(
-      const content::NavigationEntry* cur_entry,
+      const content::NavigationEntry* curr_entry,
+      const content::NavigationEntryImpl* new_entry) const;
+
+  bool ShouldReuseWebUI(
+      const content::NavigationEntry* curr_entry,
       const content::NavigationEntryImpl* new_entry) const;
 
   // Returns an appropriate SiteInstance object for the given NavigationEntry,
   // possibly reusing the current SiteInstance.
   // Never called if --process-per-tab is used.
   content::SiteInstance* GetSiteInstanceForEntry(
       const content::NavigationEntryImpl& entry,
       content::SiteInstance* curr_instance);
 
   // Helper method to create a pending RenderViewHost for a cross-site
@@ skipping 37 matching lines @@
   // non-DOM-UI pages). This object is responsible for all communication with
   // a child RenderView instance.
   content::RenderViewHostImpl* render_view_host_;
   scoped_ptr<WebUIImpl> web_ui_;
 
   // A RenderViewHost used to load a cross-site page. This remains hidden
   // while a cross-site request is pending until it calls DidNavigate. It may
   // have an associated Web UI, in which case the Web UI pointer will be non-
   // NULL.
   //
-  // The pending_web_ui may be non-NULL even when the pending_render_view_host_
-  // is. This will happen when we're transitioning between two Web UI pages:
-  // the RVH won't be swapped, so the pending pointer will be unused, but there
-  // will be a pending Web UI associated with the navigation.
+  // The |pending_web_ui_| may be non-NULL even when the
+  // |pending_render_view_host_| is NULL. This will happen when we're
+  // transitioning between two Web UI pages: the RVH won't be swapped, so the
+  // pending pointer will be unused, but there will be a pending Web UI
+  // associated with the navigation.
   content::RenderViewHostImpl* pending_render_view_host_;
+
+  // If either of these is non-NULL, the pending navigation is to a chrome:
+  // page. The scoped_ptr is used if pending_web_ui_ != web_ui_, the WeakPtr is
+  // used for when they reference the same object. If either is non-NULL, the
+  // other should be NULL.
   scoped_ptr<WebUIImpl> pending_web_ui_;
+  base::WeakPtr<WebUIImpl> pending_and_current_web_ui_;
 
   // A map of site instance ID to swapped out RenderViewHosts.
   typedef base::hash_map<int32, content::RenderViewHostImpl*> RenderViewHostMap;
   RenderViewHostMap swapped_out_hosts_;
 
   // The intersitial page currently shown if any, not own by this class
   // (the InterstitialPage is self-owned, it deletes itself when hidden).
   InterstitialPageImpl* interstitial_page_;
 
   content::NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderViewHostManager);
 };
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_RENDER_VIEW_HOST_MANAGER_H_