Adding AMP cache PageLoad.* metrics

chrome/browser/BUILD.gn

 # 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.
 
 import("//build/config/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 736 matching lines @@
     "ntp_tiles/chrome_popular_sites_factory.cc",
     "ntp_tiles/chrome_popular_sites_factory.h",
     "page_load_metrics/browser_page_track_decider.cc",
     "page_load_metrics/browser_page_track_decider.h",
     "page_load_metrics/metrics_navigation_throttle.cc",
     "page_load_metrics/metrics_navigation_throttle.h",
     "page_load_metrics/metrics_web_contents_observer.cc",
     "page_load_metrics/metrics_web_contents_observer.h",
     "page_load_metrics/observers/aborts_page_load_metrics_observer.cc",
     "page_load_metrics/observers/aborts_page_load_metrics_observer.h",
+    "page_load_metrics/observers/amp_page_load_metrics_observer.cc",
+    "page_load_metrics/observers/amp_page_load_metrics_observer.h",
     "page_load_metrics/observers/core_page_load_metrics_observer.cc",
     "page_load_metrics/observers/core_page_load_metrics_observer.h",
     "page_load_metrics/observers/css_scanning_page_load_metrics_observer.cc",
     "page_load_metrics/observers/css_scanning_page_load_metrics_observer.h",
     "page_load_metrics/observers/data_reduction_proxy_metrics_observer.cc",
     "page_load_metrics/observers/data_reduction_proxy_metrics_observer.h",
     "page_load_metrics/observers/document_write_page_load_metrics_observer.cc",
     "page_load_metrics/observers/document_write_page_load_metrics_observer.h",
     "page_load_metrics/observers/from_gws_page_load_metrics_observer.cc",
     "page_load_metrics/observers/from_gws_page_load_metrics_observer.h",
@@ skipping 3698 matching lines @@
   # linking all of the test support.
   static_library("pepper_cdm_test_constants") {
     testonly = true
     visibility = [ "//chrome/*" ]
     sources = [
       "media/pepper_cdm_test_constants.cc",
       "media/pepper_cdm_test_constants.h",
     ]
   }
 }