New TimeToFirstURLJob* navigation metrics now work with PlzNavigate.

content/browser/loader/navigation_url_loader_impl_core.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/loader/navigation_url_loader_impl_core.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "content/browser/frame_host/navigation_request_info.h"
 #include "content/browser/loader/navigation_resource_handler.h"
@@ skipping 83 matching lines @@
 
 void NavigationURLLoaderImplCore::NotifyRequestFailed(int net_error) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       base::Bind(&NavigationURLLoaderImpl::NotifyRequestFailed, loader_,
                  net_error));
 }
 
+void NavigationURLLoaderImplCore::AboutToBeginNavigation(
+    base::TimeTicks timestamp) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&NavigationURLLoaderImpl::AboutToBeginNavigation, loader_,
+                 timestamp));
+}
+
 }  // namespace content