PlzNavigate: Speculatively spawns a renderer process for navigations.

content/browser/frame_host/render_frame_host_manager.cc

Index: content/browser/frame_host/render_frame_host_manager.cc
diff --git a/content/browser/frame_host/render_frame_host_manager.cc b/content/browser/frame_host/render_frame_host_manager.cc
index 06ab825123e4b1fd294dd577e6aee18ab9ff94fe..3970e13cd66f7df5c7d6a9de6a8b3958ec43294c 100644
--- a/content/browser/frame_host/render_frame_host_manager.cc
+++ b/content/browser/frame_host/render_frame_host_manager.cc
@@ -61,7 +61,8 @@ RenderFrameHostManager::RenderFrameHostManager(
       render_view_delegate_(render_view_delegate),
       render_widget_delegate_(render_widget_delegate),
       interstitial_page_(NULL),
-      weak_factory_(this) {
+      weak_factory_(this),
+      should_reuse_web_ui_(false) {
   DCHECK(frame_tree_node_);
 }
 
@@ -69,6 +70,11 @@ RenderFrameHostManager::~RenderFrameHostManager() {
   if (pending_render_frame_host_)
     CancelPending();
 
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableBrowserSideNavigation)) {
+    CleanUpNavigation();
+  }
+
   // We should always have a current RenderFrameHost except in some tests.
   SetRenderFrameHost(scoped_ptr<RenderFrameHostImpl>());
 
@@ -288,6 +294,8 @@ void RenderFrameHostManager::OnBeforeUnloadACK(
     bool proceed,
     const base::TimeTicks& proceed_time) {
   if (for_cross_site_transition) {
+    DCHECK(!CommandLine::ForCurrentProcess()->HasSwitch(
+        switches::kEnableBrowserSideNavigation));
     // Ignore if we're not in a cross-site navigation.
     if (!cross_navigation_pending_)
       return;
@@ -419,6 +427,12 @@ void RenderFrameHostManager::ClearNavigationTransitionData() {
 
 void RenderFrameHostManager::DidNavigateFrame(
     RenderFrameHostImpl* render_frame_host) {
+  DCHECK(render_frame_host);
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableBrowserSideNavigation)) {
+    return;
+  }
+
   if (!cross_navigation_pending_) {
     DCHECK(!pending_render_frame_host_);
 
@@ -619,6 +633,88 @@ void RenderFrameHostManager::ResetProxyHosts() {
 }
 
 // PlzNavigate
+void RenderFrameHostManager::BeginNavigation(
+    const FrameHostMsg_BeginNavigation_Params& params,
+    const CommonNavigationParams& common_params) {
+  CHECK(CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableBrowserSideNavigation));
+  // If there is an ongoing navigation, cancel it.
+  CleanUpNavigation();
+
+  SiteInstance* current_instance = render_frame_host_->GetSiteInstance();
+  // TODO(carlosk): Replace the default values with the right ones.
+  scoped_refptr<SiteInstanceImpl> new_instance =
+      static_cast<SiteInstanceImpl*>(GetSiteInstanceForNavigation(
+          common_params.url, nullptr, common_params.transition, false, false));
+
+  if (new_instance.get() != current_instance &&
+      (frame_tree_node_->IsMainFrame() ||
+       CommandLine::ForCurrentProcess()->HasSwitch(
+           switches::kSitePerProcess))) {
+    // Navigating to a new SiteInstance -> speculatively create a new RFH.
+
+    // TODO(carlosk): enable bindings check below.
+    bool success = CreateSpeculativeRenderFrameHost(
+        common_params.url, current_instance, new_instance.get(),
+        NavigationEntryImpl::kInvalidBindings);
+    if (!success)
+      return;
+    DCHECK(new_instance->GetProcess()->HasConnection());
+    DCHECK(new_instance->GetProcess()->GetBrowserContext());
+  } else {
+    // Navigating to the same SiteInstance -> make sure the current RFH is
+    // alive.
+    if (!render_frame_host_->render_view_host()->IsRenderViewLive()) {
+      // Recreate the opener chain.
+      int opener_route_id = delegate_->CreateOpenerRenderViewsForRenderManager(
+          render_frame_host_->GetSiteInstance());
+      if (!InitRenderView(render_frame_host_->render_view_host(),
+                          opener_route_id, MSG_ROUTING_NONE,
+                          frame_tree_node_->IsMainFrame())) {
+        return;
+      }
+    }
+    DCHECK(current_instance->GetProcess()->HasConnection());
+    DCHECK(current_instance->GetProcess()->GetBrowserContext());
+  }
+}
+
+// PlzNavigate
+bool RenderFrameHostManager::CreateSpeculativeRenderFrameHost(
+    const GURL& url,
+    SiteInstance* old_instance,
+    SiteInstance* new_instance,
+    int bindings) {
+  CHECK(new_instance);
+  CHECK_NE(old_instance, new_instance);
+
+  const NavigationEntry* current_navigation_entry =
+      delegate_->GetLastCommittedNavigationEntryForRenderManager();
+  scoped_ptr<WebUIImpl> new_web_ui;
+  should_reuse_web_ui_ = ShouldReuseWebUI(current_navigation_entry, url);
+  if (!should_reuse_web_ui_)
+    new_web_ui = CreateWebUI(url, bindings);
+
+  int opener_route_id =
+      CreateOpenerRenderViewsIfNeeded(old_instance, new_instance);
+
+  int create_render_frame_flags = 0;
+  if (frame_tree_node_->IsMainFrame())
+    create_render_frame_flags |= CREATE_RF_FOR_MAIN_FRAME_NAVIGATION;
+  if (delegate_->IsHidden())
+    create_render_frame_flags |= CREATE_RF_HIDDEN;
+  scoped_ptr<RenderFrameHostImpl> new_render_frame_host =
+      CreateRenderFrame(new_instance, new_web_ui.get(), opener_route_id,
+                        create_render_frame_flags, nullptr);
+  if (!new_render_frame_host) {
+    return false;
+  }
+  speculative_render_frame_host_.reset(new_render_frame_host.release());
+  speculative_web_ui_.reset(new_web_ui.release());
+  return true;
+}
+
+// PlzNavigate
 RenderFrameHostImpl* RenderFrameHostManager::GetFrameHostForNavigation(
       const GURL& url,
       ui::PageTransition transition) {
@@ -650,6 +746,18 @@ RenderFrameHostImpl* RenderFrameHostManager::GetFrameHostForNavigation(
   return render_frame_host;
 }
 
+// PlzNavigate
+void RenderFrameHostManager::CleanUpNavigation() {
+  CHECK(CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableBrowserSideNavigation));
+  if (speculative_render_frame_host_) {
+    speculative_render_frame_host_->GetProcess()->RemovePendingView();
+    DiscardUnusedFrame(speculative_render_frame_host_.Pass());
+  }
+  if (speculative_web_ui_)
+    speculative_web_ui_.reset();
+}
+
 void RenderFrameHostManager::Observe(
     int type,
     const NotificationSource& source,
@@ -1110,8 +1218,8 @@ scoped_ptr<RenderFrameHostImpl> RenderFrameHostManager::CreateRenderFrame(
   if (view_routing_id_ptr)
     *view_routing_id_ptr = MSG_ROUTING_NONE;
 
-  // We are creating a pending or swapped out RFH here. We should never create
-  // it in the same SiteInstance as our current RFH.
+  // We are creating a pending, speculative or swapped out RFH here. We should
+  // never create it in the same SiteInstance as our current RFH.
   CHECK_NE(render_frame_host_->GetSiteInstance(), instance);
 
   // Check if we've already created an RFH for this SiteInstance.  If so, try
@@ -1288,29 +1396,38 @@ int RenderFrameHostManager::GetRoutingIdForSiteInstance(
 void RenderFrameHostManager::CommitPending() {
   TRACE_EVENT1("navigation", "RenderFrameHostManager::CommitPending",
                "FrameTreeNode id", frame_tree_node_->frame_tree_node_id());
+  bool use_speculative_rfh = CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableBrowserSideNavigation);
+
   // First check whether we're going to want to focus the location bar after
   // this commit.  We do this now because the navigation hasn't formally
   // committed yet, so if we've already cleared |pending_web_ui_| the call chain
   // this triggers won't be able to figure out what's going on.
   bool will_focus_location_bar = delegate_->FocusLocationBarByDefault();
 
-  // Next commit the Web UI, if any. Either replace |web_ui_| with
-  // |pending_web_ui_|, or clear |web_ui_| if there is no pending WebUI, or
-  // leave |web_ui_| as is if reusing it.
-  DCHECK(!(pending_web_ui_.get() && pending_and_current_web_ui_.get()));
-  if (pending_web_ui_) {
-    web_ui_.reset(pending_web_ui_.release());
-  } else if (!pending_and_current_web_ui_.get()) {
-    web_ui_.reset();
+  if (!use_speculative_rfh) {
+    DCHECK(!speculative_web_ui_);
+    // Next commit the Web UI, if any. Either replace |web_ui_| with
+    // |pending_web_ui_|, or clear |web_ui_| if there is no pending WebUI, or
+    // leave |web_ui_| as is if reusing it.
+    DCHECK(!(pending_web_ui_.get() && pending_and_current_web_ui_.get()));
+    if (pending_web_ui_) {
+      web_ui_.reset(pending_web_ui_.release());
+    } else if (!pending_and_current_web_ui_.get()) {
+      web_ui_.reset();
+    } else {
+      DCHECK_EQ(pending_and_current_web_ui_.get(), web_ui_.get());
+      pending_and_current_web_ui_.reset();
+    }
   } else {
-    DCHECK_EQ(pending_and_current_web_ui_.get(), web_ui_.get());
-    pending_and_current_web_ui_.reset();
+    if (!should_reuse_web_ui_)
+      web_ui_.reset(speculative_web_ui_.release());
   }
 
   // It's possible for the pending_render_frame_host_ to be NULL when we aren't
   // crossing process boundaries. If so, we just needed to handle the Web UI
   // committing above and we're done.
-  if (!pending_render_frame_host_) {
+  if (!pending_render_frame_host_ && !use_speculative_rfh) {
     if (will_focus_location_bar)
       delegate_->SetFocusToLocationBar(false);
     return;
@@ -1324,10 +1441,19 @@ void RenderFrameHostManager::CommitPending() {
 
   bool is_main_frame = frame_tree_node_->IsMainFrame();
 
-  // Swap in the pending frame and make it active. Also ensure the FrameTree
-  // stays in sync.
-  scoped_ptr<RenderFrameHostImpl> old_render_frame_host =
-      SetRenderFrameHost(pending_render_frame_host_.Pass());
+  scoped_ptr<RenderFrameHostImpl> old_render_frame_host;
+  if (!use_speculative_rfh) {
+    DCHECK(!speculative_render_frame_host_);
+    // Swap in the pending frame and make it active. Also ensure the FrameTree
+    // stays in sync.
+    old_render_frame_host =
+        SetRenderFrameHost(pending_render_frame_host_.Pass());
+  } else {
+    DCHECK(speculative_render_frame_host_);
+    old_render_frame_host =
+        SetRenderFrameHost(speculative_render_frame_host_.Pass());
+  }
+
   if (is_main_frame)
     render_frame_host_->render_view_host()->AttachToFrameTree();
 
@@ -1456,6 +1582,36 @@ RenderFrameHostImpl* RenderFrameHostManager::UpdateStateForNavigate(
   scoped_refptr<SiteInstance> new_instance = GetSiteInstanceForNavigation(
       url, instance, transition, is_restore, is_view_source_mode);
 
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableBrowserSideNavigation)) {
+    if (current_instance == new_instance.get() ||
+        (!frame_tree_node_->IsMainFrame() &&
+         !CommandLine::ForCurrentProcess()->HasSwitch(
+             switches::kSitePerProcess))) {
+      CleanUpNavigation();
+    } else {
+      // If the SiteInstance for the final URL doesn't match the one form the
+      // speculatively created RenderFrameHost, create a new one using the
+      // former.
+      if (!speculative_render_frame_host_ ||
+          speculative_render_frame_host_->GetSiteInstance() !=
+              new_instance.get()) {
+        CleanUpNavigation();
+        // TODO(carlosk): Should rename this method and the speculative members
+        // because in this case they are not speculative. Suggestions are
+        // very welcome!
+        bool success = CreateSpeculativeRenderFrameHost(
+            url, current_instance, new_instance.get(), bindings);
+        if (!success)
+          return nullptr;
+      }
+      DCHECK(speculative_render_frame_host_);
+      CommitPending();
+      DCHECK(!speculative_render_frame_host_);
+    }
+    return render_frame_host_.get();
+  }
+
   const NavigationEntry* current_entry =
       delegate_->GetLastCommittedNavigationEntryForRenderManager();