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 17 matching lines @@
     return;
   }
 
   // In all other cases the current navigation, if any, is canceled and a new
   // NavigationRequest is created for the node.
   scoped_ptr<NavigationRequest> navigation_request =
       NavigationRequest::CreateRendererInitiated(
           frame_tree_node, common_params, begin_params, body,
           controller_->GetLastCommittedEntryIndex(),
           controller_->GetEntryCount());
   frame_tree_node->SetNavigationRequest(navigation_request.Pass());

[nasko, 2015/06/12 17:22:22]

If you've eliminated the local scoped_ptr in RequestNavigation and this method
is already being modified, might as well standardize on one pattern and use it.

[carlosk, 2015/06/15 19:11:54]

Done.

My initial thought was that as it is used it only once here (there it was used
many times) I'd keep the diff simpler by not making this change. Still trying to
find the correct balance.

I was tempted to merge the now raw navigation_request pointer with the
ongoing_navigation_request above but felt like this split make things clearer.

 
   if (frame_tree_node->IsMainFrame()) {
     // Renderer-initiated main-frame navigations that need to swap processes
     // will go to the browser via a OpenURL call, and then be handled by the
     // same code path as browser-initiated navigations. For renderer-initiated
     // 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);
+  frame_tree_node->navigation_request()->BeginNavigation();
 }
 
 // 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 127 matching lines @@
 
 // PlzNavigate
 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);
+
+  // This value must be set here because SetNavigationRequest might change the
+  // renderer live/non-live status and change this result.
+  bool should_dispatch_beforeunload =
+      frame_tree_node->current_frame_host()->ShouldDispatchBeforeUnload();
   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).
-  if (NavigationRequest::ShouldMakeNetworkRequest(
-          frame_tree_node->navigation_request()->common_params().url)) {
+  // is not needed NavigationRequest::BeginNavigation should get called. This is
+  // the case if the renderer is not live, this is a subframe navigation, or if

[nasko, 2015/06/12 17:22:22]

The details of when running the beforeUnload handler is required or not
shouldn't be documented here, but rather at ShouldDispatchBeforeUnload.

[carlosk, 2015/06/15 19:11:54]

I'm assuming the same logic applies to the details concerning
ShouldMakeNetworkRequest.

So I updated this comment to not go into either of them and moved information
out to the declaration of ShouldMakeNetworkRequest (ShouldDispatchBeforeUnload
already had the concerned details).

+  // the navigation is synchronous and same-site (such as for data URLs or
+  // Javascript URLs, when no network request is made).
+  if (should_dispatch_beforeunload &&
+      NavigationRequest::ShouldMakeNetworkRequest(
+          navigation_request->common_params().url)) {
+    navigation_request->SetWaitingForRendererResponse();
     frame_tree_node->current_frame_host()->DispatchBeforeUnload(true);
   } else {
-    BeginNavigation(frame_tree_node);
+    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