Record UMA for parser blocking time for scripts inserted via doc.write

components/page_load_metrics/common/page_load_timing.h

 // 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.
 
 #ifndef COMPONENTS_PAGE_LOAD_METRICS_COMMON_PAGE_LOAD_TIMING_H_
 #define COMPONENTS_PAGE_LOAD_METRICS_COMMON_PAGE_LOAD_TIMING_H_
 
 #include "base/time/time.h"
 
 namespace page_load_metrics {
@@ skipping 44 matching lines @@
   // Time that the document's parser started and stopped parsing main resource
   // content.
   base::TimeDelta parse_start;
   base::TimeDelta parse_stop;
 
   // Sum of times when the parser is blocked waiting on the load of a script.
   // This duration takes place between parser_start and parser_stop, and thus
   // must be less than or equal to parser_stop - parser_start.
   base::TimeDelta parse_blocked_on_script_load_duration;
 
+  // Sum of times when the parser is blocked waiting on the load of a script
+  // that was inserted from document.write. This duration must be less than or
+  // equal to parse_blocked_on_script_load_duration. Note that some uncommon
+  // cases where scripts are loaded via document.write are not currently covered
+  // by this field. See crbug/600711 for details.
+  base::TimeDelta parse_blocked_on_script_load_from_document_write_duration;
+
   // If you add additional members, also be sure to update operator==,
   // page_load_metrics_messages.h, and IsEmpty().
 };
 
 }  // namespace page_load_metrics
 
 #endif  // COMPONENTS_PAGE_LOAD_METRICS_COMMON_PAGE_LOAD_TIMING_H_