New TimeToFirstURLJob* navigation metrics now work with PlzNavigate.

content/browser/frame_host/navigator_impl.cc

Index: content/browser/frame_host/navigator_impl.cc
diff --git a/content/browser/frame_host/navigator_impl.cc b/content/browser/frame_host/navigator_impl.cc
index ebd10e9739d85a3dbb38636447002fd1893e0df6..8030813fa562001fa5d9aaff3faad60f61b3eb1b 100644
--- a/content/browser/frame_host/navigator_impl.cc
+++ b/content/browser/frame_host/navigator_impl.cc
@@ -772,6 +772,7 @@ void NavigatorImpl::OnBeginNavigation(
     navigation_request = scoped_request.get();
     navigation_request_map_.set(
         frame_tree_node->frame_tree_node_id(), scoped_request.Pass());
+    navigation_data_.reset();

[davidben, 2015/02/02 22:33:57]

Does this also need an IsMainFrame guard?

[carlosk, 2015/02/03 11:00:04]

No because here we actually want it to be reset. This if-block handles
renderer-initiated navigations which we don't want to track.

[clamy, 2015/02/03 12:13:54]

I think we should have one for the case where the user starts a browser intiated
navigation in the main frame and a renderer initiated navigation starts in a
subframe. We don't want to discard the data coming from the main frame
navigation that will eventually commit.

[carlosk, 2015/02/03 12:48:34]

You are both right indeed, sorry. Done.

   }
   DCHECK(navigation_request);
 
@@ -833,6 +834,8 @@ void NavigatorImpl::CancelNavigation(FrameTreeNode* frame_tree_node) {
   CHECK(base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableBrowserSideNavigation));
   navigation_request_map_.erase(frame_tree_node->frame_tree_node_id());
+  if (frame_tree_node->IsMainFrame())
+    navigation_data_.reset();
   // TODO(carlosk): move this cleanup into the NavigationRequest destructor once
   // we properly cancel ongoing navigations.
   frame_tree_node->render_manager()->CleanUpNavigation();
@@ -944,6 +947,7 @@ void NavigatorImpl::RecordNavigationMetrics(
     RecordAction(base::UserMetricsAction("FrameLoad"));
 
   if (!details.is_main_frame || !navigation_data_ ||
+      navigation_data_->url_job_start_time_.is_null() ||

[carlosk, 2015/01/30 14:01:47]

I realized that if for some reason NavigatorImpl::LogResourceRequestTime was not
called before commit then |navigation_data_->url_job_start_time_| would not be
set and we would record invalid values. Just in case, I'm updating
NavigatorImpl::RecordNavigationMetrics so that it doesn't try to record anything
if it was not set.

       navigation_data_->url_ != params.original_request_url) {
     return;
   }