Adding MHTML support into Page Load Metrics

chrome/browser/page_load_metrics/page_load_metrics_observer.cc

 // 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.
 
 #include "chrome/browser/page_load_metrics/page_load_metrics_observer.h"
 
 namespace page_load_metrics {
 
 PageLoadExtraInfo::PageLoadExtraInfo(
     const base::Optional<base::TimeDelta>& first_background_time,
@@ skipping 67 matching lines @@
   return CONTINUE_OBSERVING;
 }
 
 PageLoadMetricsObserver::ObservePolicy
 PageLoadMetricsObserver::FlushMetricsOnAppEnterBackground(
     const PageLoadTiming& timing,
     const PageLoadExtraInfo& extra_info) {
   return CONTINUE_OBSERVING;
 }
 
+PageLoadMetricsObserver::ObservePolicy
+PageLoadMetricsObserver::ShouldObserveMimeType(
+    const std::string& mime_type) const {
+  return mime_type == "text/html" || mime_type == "application/xhtml+xml"
+             ? CONTINUE_OBSERVING
+             : STOP_OBSERVING;
+}
+
 }  // namespace page_load_metrics