[page_load_metrics] Add a NavigationThrottle for richer abort metrics

components/page_load_metrics.gypi

 # Copyright 2015 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.
 
 {
   'conditions': [
     ['OS != "ios"', {
       'targets': [
         {
           'target_name': 'page_load_metrics_common',
@@ skipping 18 matching lines @@
           'dependencies': [
             '../base/base.gyp:base',
             '../content/content.gyp:content_browser',
             '../ipc/ipc.gyp:ipc',
             'page_load_metrics_common',
           ],
           'include_dirs': [
             '..',
           ],
           'sources': [
+            'page_load_metrics/browser/metrics_navigation_throttle.cc',
+            'page_load_metrics/browser/metrics_navigation_throttle.h',
             'page_load_metrics/browser/metrics_web_contents_observer.cc',
             'page_load_metrics/browser/metrics_web_contents_observer.h',
             'page_load_metrics/browser/page_load_metrics_observer.cc',
             'page_load_metrics/browser/page_load_metrics_observer.h',
             'page_load_metrics/browser/page_load_metrics_util.cc',
             'page_load_metrics/browser/page_load_metrics_util.h',
           ],
         },
         {
           'target_name': 'page_load_metrics_renderer',
@@ skipping 12 matching lines @@
             'page_load_metrics/renderer/metrics_render_frame_observer.cc',
             'page_load_metrics/renderer/metrics_render_frame_observer.h',
             'page_load_metrics/renderer/page_timing_metrics_sender.cc',
             'page_load_metrics/renderer/page_timing_metrics_sender.h',
           ],
         },
       ],
     }]
   ]
 }