New TimeToFirstURLJob* navigation metrics now work with PlzNavigate.

content/browser/frame_host/navigation_request.cc

 // Copyright 2014 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/navigation_request.h"
 
 #include "content/browser/frame_host/frame_tree_node.h"
 #include "content/browser/frame_host/navigation_request_info.h"
 #include "content/browser/frame_host/navigator.h"
 #include "content/browser/loader/navigation_url_loader.h"
@@ skipping 90 matching lines @@
   DCHECK(state_ == STARTED);
   state_ = RESPONSE_STARTED;
   frame_tree_node_->navigator()->CommitNavigation(frame_tree_node_,
                                                   response.get(), body.Pass());
 }
 
 void NavigationRequest::OnRequestFailed(int net_error) {
   DCHECK(state_ == STARTED);
   state_ = FAILED;
   // TODO(davidben): Network failures should display a network error page.
-  NOTIMPLEMENTED();
+  NOTIMPLEMENTED() << " where net_error=" << net_error;

[carlosk, 2015/01/26 19:54:01]

Added this little extra logging to help with debugging.

+}
+
+void NavigationRequest::AboutToBeginNavigation(base::TimeTicks timestamp) {
+  frame_tree_node_->navigator()->LogAboutToBeginNavigation(timestamp);
 }
 
 }  // namespace content