PlzNavigate: Create the speculative renderer earlier.

content/browser/frame_host/navigator_impl.cc

 // 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.
 
 #include "content/browser/frame_host/navigator_impl.h"
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
 #include "base/time/time.h"
 #include "content/browser/frame_host/frame_tree.h"
@@ skipping 582 matching lines @@
   NavigationRequest* navigation_request = frame_tree_node->navigation_request();
 
   // The NavigationRequest may have been canceled while the renderer was
   // executing the BeforeUnload event.
   if (!navigation_request)
     return;
 
   DCHECK_EQ(NavigationRequest::WAITING_FOR_RENDERER_RESPONSE,
             navigation_request->state());
 
+  // If the navigation is allowed to proceed, send the request to the IO thread.
   if (proceed)
-    BeginNavigation(frame_tree_node);
+    navigation_request->BeginNavigation();
   else
     CancelNavigation(frame_tree_node);
 }
 
 // PlzNavigate
 void NavigatorImpl::OnBeginNavigation(
     FrameTreeNode* frame_tree_node,
     const CommonNavigationParams& common_params,
     const BeginNavigationParams& begin_params,
     scoped_refptr<ResourceRequestBody> body) {
@@ skipping 33 matching lines @@
     // main frame navigation that start via a BeginNavigation IPC, the
     // RenderFrameHost will not be swapped. Therefore it is safe to call
     // DidStartMainFrameNavigation with the SiteInstance from the current
     // RenderFrameHost.
     DidStartMainFrameNavigation(
         common_params.url,
         frame_tree_node->current_frame_host()->GetSiteInstance());
     navigation_data_.reset();
   }
 
-  BeginNavigation(frame_tree_node);
+  if (frame_tree_node->navigation_request()->BeginNavigation()) {
+    // If the request was really sent to the IO thread, notify the
+    // RenderFrameHostManager so it can speculatively create a RenderFrameHost
+    // (and potentially a new renderer process) in parallel.
+    frame_tree_node->render_manager()->BeginNavigation(
+        *frame_tree_node->navigation_request());
+  }
 }
 
 // PlzNavigate
 void NavigatorImpl::CommitNavigation(FrameTreeNode* frame_tree_node,
                                      ResourceResponse* response,
                                      scoped_ptr<StreamHandle> body) {
   CHECK(base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableBrowserSideNavigation));
 
   NavigationRequest* navigation_request = frame_tree_node->navigation_request();
@@ skipping 129 matching lines @@
 void NavigatorImpl::RequestNavigation(
     FrameTreeNode* frame_tree_node,
     const NavigationEntryImpl& entry,
     NavigationController::ReloadType reload_type,
     base::TimeTicks navigation_start) {
   CHECK(base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableBrowserSideNavigation));
   DCHECK(frame_tree_node);
   FrameMsg_Navigate_Type::Value navigation_type =
       GetNavigationType(controller_->GetBrowserContext(), entry, reload_type);
-  scoped_ptr<NavigationRequest> navigation_request =
+  frame_tree_node->SetNavigationRequest(
       NavigationRequest::CreateBrowserInitiated(frame_tree_node, entry,
                                                 navigation_type,
-                                                navigation_start, controller_);
-  frame_tree_node->SetNavigationRequest(navigation_request.Pass());
-  frame_tree_node->navigation_request()->SetWaitingForRendererResponse();
+                                                navigation_start, controller_));
+  NavigationRequest* navigation_request = frame_tree_node->navigation_request();
 
-  // Have the current renderer execute its beforeUnload event if needed. If it
-  // is not needed (eg. the renderer is not live), BeginNavigation should get
-  // called. If the navigation is synchronous and same-site, then it can be sent
-  // directly to the renderer (currently this is the case for navigations that
-  // do not make network requests such as data urls or Javascript urls).
+  // Have the current renderer execute its beforeunload event if needed.
   if (NavigationRequest::ShouldMakeNetworkRequest(

[clamy, 2015/06/09 10:02:01]

I find the new ordering of comments not clearer. I think having the paragraph
summary was simpler. This will be even more the case if you move the call to
RFHM inside FrameTreeNode.

[carlosk, 2015/06/09 15:33:51]

Reverted to the previous comment with slight adaptations.

-          frame_tree_node->navigation_request()->common_params().url)) {
+          navigation_request->common_params().url)) {
+    // If this navigation is not synchronous dispatch the beforeunload request.
+    navigation_request->SetWaitingForRendererResponse();
     frame_tree_node->current_frame_host()->DispatchBeforeUnload(true);
+    // Note: At this point if beforeunload was deemed not needed (i.e. there
+    // was no live renderer) then the request to the IO thread has already been
+    // sent.
+    frame_tree_node->render_manager()->BeginNavigation(*navigation_request);
   } else {
-    BeginNavigation(frame_tree_node);
+    // If the navigation is synchronous and same-site, then the current renderer
+    // will be reused and the NavigationRequest will just commit the navigation.
+    // This is currently the case for navigations that do not make network
+    // requests such as data URLs or Javascript URLs.
+    navigation_request->BeginNavigation();
   }
 }
 
-void NavigatorImpl::BeginNavigation(FrameTreeNode* frame_tree_node) {
-  NavigationRequest* navigation_request = frame_tree_node->navigation_request();
-
-  // A browser-initiated navigation could have been cancelled while it was
-  // waiting for the BeforeUnload event to execute.
-  if (!navigation_request)
-    return;
-
-  // Start the request.
-   if (navigation_request->BeginNavigation()) {
-    // If the request was sent to the IO thread, notify the
-    // RenderFrameHostManager so it can speculatively create a RenderFrameHost
-    // (and potentially a new renderer process) in parallel.
-    frame_tree_node->render_manager()->BeginNavigation(*navigation_request);
-  }
-}
-
 void NavigatorImpl::RecordNavigationMetrics(
     const LoadCommittedDetails& details,
     const FrameHostMsg_DidCommitProvisionalLoad_Params& params,
     SiteInstance* site_instance) {
   DCHECK(site_instance->HasProcess());
 
   if (!details.is_in_page)
     RecordAction(base::UserMetricsAction("FrameLoad"));
 
   if (!details.is_main_frame || !navigation_data_ ||
@@ skipping 67 matching lines @@
       entry->set_should_replace_entry(pending_entry->should_replace_entry());
       entry->SetRedirectChain(pending_entry->GetRedirectChain());
     }
     controller_->SetPendingEntry(entry);
     if (delegate_)
       delegate_->NotifyChangedNavigationState(content::INVALIDATE_TYPE_URL);
   }
 }
 
 }  // namespace content