PlzNavigate: Speculatively spawns a renderer process for navigations.

content/browser/frame_host/render_frame_host_manager.h

 // Copyright 2013 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_FRAME_HOST_RENDER_FRAME_HOST_MANAGER_H_
 #define CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_MANAGER_H_
 
 #include <list>
 
 #include "base/basictypes.h"
@@ skipping 13 matching lines @@
 
 namespace content {
 class BrowserContext;
 class CrossProcessFrameConnector;
 class CrossSiteTransferringRequest;
 class FrameTreeNode;
 class InterstitialPageImpl;
 class NavigationControllerImpl;
 class NavigationEntry;
 class NavigationEntryImpl;
+class NavigatorTestWithBrowserSideNavigation;
 class RenderFrameHost;
 class RenderFrameHostDelegate;
 class RenderFrameHostImpl;
 class RenderFrameHostManagerTest;
 class RenderFrameProxyHost;
 class RenderViewHost;
 class RenderViewHostImpl;
 class RenderWidgetHostDelegate;
 class RenderWidgetHostView;
 class TestWebContents;
 class WebUIImpl;
+struct CommonNavigationParams;
 
 // Manages RenderFrameHosts for a FrameTreeNode. It maintains a
 // current_frame_host() which is the content currently visible to the user. When
 // a frame is told to navigate to a different web site (as determined by
 // SiteInstance), it will replace its current RenderFrameHost with a new
 // RenderFrameHost dedicated to the new SiteInstance, possibly in a new process.
 //
 // Cross-process navigation works like this:
 //
 // - RFHM::Navigate determines whether the destination is cross-site, and if so,
@@ skipping 305 matching lines @@
 
   // Deletes any proxy hosts associated with this node. Used during destruction
   // of WebContentsImpl.
   void ResetProxyHosts();
 
   // Returns the routing id for a RenderFrameHost or RenderFrameHostProxy
   // that has the given SiteInstance and is associated with this
   // RenderFrameHostManager. Returns MSG_ROUTING_NONE if none is found.
   int GetRoutingIdForSiteInstance(SiteInstance* site_instance);
 
-  // PlzNavigate: Called when a navigation is ready to commit, to select the
-  // renderer that will commit it.
+  // PlzNavigate
+  // Notifies the RFHM that a navigation has begun so that it can speculatively
+  // create a new RenderFrameHost (and potentially a new process) if needed.
+  void BeginNavigation(const CommonNavigationParams& common_params);
+
+  // PlzNavigate
+  // Called (possibly several times) during a navigation to select an

[Charlie Reis, 2015/01/12 23:30:53]

nit: select or create

[carlosk, 2015/01/13 15:54:13]

Done.

+  // appropriate RenderFrameHost for the provided URL.
   RenderFrameHostImpl* GetFrameHostForNavigation(const GURL& url,

[Charlie Reis, 2015/01/12 23:30:53]

The ownership of this RFH is unclear.  Please document that the return value
will already be owned by the RFHM, either as the current or speculative RFH.

[carlosk, 2015/01/13 15:54:13]

Done.

                                                  ui::PageTransition transition);
 
+  // PlzNavigate
+  // Clean up any state for any ongoing navigation.
+  void CleanUpNavigation();
+
+  // PlzNavigate
+  // Clears the speculative members, returning the RenderFrameHost to the caller
+  // for disposal.
+  scoped_ptr<RenderFrameHostImpl> UnsetSpeculativeRenderFrameHost();
+
   // Notification methods to tell this RenderFrameHostManager that the frame it
   // is responsible for has started or stopped loading a document.
   void OnDidStartLoading();
   void OnDidStopLoading();
 
  private:
+  friend class NavigatorTestWithBrowserSideNavigation;
   friend class RenderFrameHostManagerTest;
   friend class TestWebContents;
 
   FRIEND_TEST_ALL_PREFIXES(CrossProcessFrameTreeBrowserTest,
                            CreateCrossProcessSubframeProxies);
 
   // Used with FrameTree::ForEach to erase RenderFrameProxyHosts from a
   // FrameTreeNode's RenderFrameHostManager.
   static bool ClearProxiesInSiteInstance(int32 site_instance_id,
                                          FrameTreeNode* node);
@@ skipping 80 matching lines @@
   // route ID to be used for the new RenderView to be created.
   int CreateOpenerRenderViewsIfNeeded(SiteInstance* old_instance,
                                       SiteInstance* new_instance);
 
   // Creates a RenderFrameHost and corresponding RenderViewHost if necessary.
   scoped_ptr<RenderFrameHostImpl> CreateRenderFrameHost(SiteInstance* instance,
                                                         int view_routing_id,
                                                         int frame_routing_id,
                                                         int flags);
 
+  // PlzNavigate
+  // Creates and initializes a speculative RenderFrameHost and/or WebUI for an
+  // ongoing navigation. They might be destroyed and re-created later if the
+  // navigation is redirected to a different SiteInstance.
+  bool CreateSpeculativeRenderFrameHost(const GURL& url,
+                                        SiteInstance* old_instance,
+                                        SiteInstance* new_instance,
+                                        int bindings);
+
   // Sets up the necessary state for a new RenderViewHost with the given opener,
   // if necessary.  It creates a RenderFrameProxy in the target renderer process
   // with the given |proxy_routing_id|, which is used to route IPC messages when
   // in swapped out state.  Returns early if the RenderViewHost has already been
   // initialized for another RenderFrameHost.
   // TODO(creis): opener_route_id is currently for the RenderViewHost but should
   // be for the RenderFrame, since frames can have openers.
   bool InitRenderView(RenderViewHostImpl* render_view_host,
                       int opener_route_id,
                       int proxy_routing_id,
                       bool for_main_frame_navigation);
 
   // Initialization for RenderFrameHost uses the same sequence as InitRenderView
   // above.
   bool InitRenderFrame(RenderFrameHostImpl* render_frame_host);
 
   // Sets the pending RenderFrameHost/WebUI to be the active one. Note that this
   // doesn't require the pending render_frame_host_ pointer to be non-NULL,
   // since there could be Web UI switching as well. Call this for every commit.
+  // If PlzNavigate is enabled the method will set the speculative (not pending)
+  // RenderFrameHost to be the active one.
   void CommitPending();
 
   // Runs the unload handler in the old RenderFrameHost, after the new
   // RenderFrameHost has committed.  |old_render_frame_host| will either be
   // deleted or put on the pending delete list during this call.
   void SwapOutOldFrame(scoped_ptr<RenderFrameHostImpl> old_render_frame_host);
 
   // Discards a RenderFrameHost that was never made active (for active ones
   // SwapOutOldFrame is used instead).
   void DiscardUnusedFrame(scoped_ptr<RenderFrameHostImpl> render_frame_host);
@@ skipping 66 matching lines @@
   // A RenderFrameHost 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_frame_host_| is NULL. This will happen when we're
   // transitioning between two Web UI pages: the RFH won't be swapped, so the
   // pending pointer will be unused, but there will be a pending Web UI
   // associated with the navigation.
+  // Note: This is not used in PlzNavigate.
   scoped_ptr<RenderFrameHostImpl> pending_render_frame_host_;
 
   // If a pending request needs to be transferred to another process, this
   // owns the request until it's transferred to the new process, so it will be
   // cleaned up if the navigation is cancelled.  Otherwise, this is NULL.
   scoped_ptr<CrossSiteTransferringRequest> cross_site_transferring_request_;
 
   // Tracks information about any navigation paused after receiving response
   // headers.
   scoped_ptr<GlobalRequestID> response_started_id_;
 
   // 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.
+  // Note: These are not used in PlzNavigate.
   scoped_ptr<WebUIImpl> pending_web_ui_;
   base::WeakPtr<WebUIImpl> pending_and_current_web_ui_;
 
   // A map of site instance ID to RenderFrameProxyHosts.
   typedef base::hash_map<int32, RenderFrameProxyHost*> RenderFrameProxyHostMap;
   RenderFrameProxyHostMap proxy_hosts_;
 
   // A list of RenderFrameHosts waiting to shut down after swapping out.  We use
   // a linked list since we expect frequent deletes and no indexed access, and
   // because sets don't appear to support linked_ptrs.
   typedef std::list<linked_ptr<RenderFrameHostImpl> > RFHPendingDeleteList;
   RFHPendingDeleteList pending_delete_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_;
 
   NotificationRegistrar registrar_;
 
+  // PlzNavigate
+  // These members store a speculative RenderFrameHost and WebUI. They are
+  // created early in a navigation so a renderer process can be started in
+  // parallel, if needed. This is purely a performance optimization and is not
+  // required for correct behavior. The created RenderFrameHost might be
+  // discarded later on if the final URL's SiteInstance isn't compatible with
+  // what was used to create it.
+  // Note: PlzNavigate only uses speculative RenderFrameHost and WebUI, not
+  // the pending ones.
+  scoped_ptr<RenderFrameHostImpl> speculative_render_frame_host_;
+  scoped_ptr<WebUIImpl> speculative_web_ui_;
+
+  // PlzNavigate
+  // If true at navigation commit time the current WebUI will be kept instead of
+  // creating a new one.
+  bool should_reuse_web_ui_;
+
   base::WeakPtrFactory<RenderFrameHostManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameHostManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_MANAGER_H_