Move PageLoadTiming TimeDelta fields to a common header.

chrome/common/page_load_metrics/page_load_timing.h

Index: chrome/common/page_load_metrics/page_load_timing.h
diff --git a/chrome/common/page_load_metrics/page_load_timing.h b/chrome/common/page_load_metrics/page_load_timing.h
index e41235b49f8f8e6805307f3ba47ae4b5447b2443..4c91bcc4643be78c943d34b6c06212d4ee16d3d7 100644
--- a/chrome/common/page_load_metrics/page_load_timing.h
+++ b/chrome/common/page_load_metrics/page_load_timing.h
@@ -30,53 +30,14 @@ struct PageLoadTiming {
   // Time that the navigation for the associated page was initiated.
   base::Time navigation_start;
 
-  // All TimeDeltas are relative to navigation_start
-
-  // Time that the first byte of the response is received.
-  base::Optional<base::TimeDelta> response_start;
-
-  // Time immediately before the DOMContentLoaded event is fired.
-  base::Optional<base::TimeDelta> dom_content_loaded_event_start;
-
-  // Time immediately before the load event is fired.
-  base::Optional<base::TimeDelta> load_event_start;
-
-  // Time when the first layout is completed.
-  base::Optional<base::TimeDelta> first_layout;
-
-  // Time when the first paint is performed.
-  base::Optional<base::TimeDelta> first_paint;
-  // Time when the first non-blank text is painted.
-  base::Optional<base::TimeDelta> first_text_paint;
-  // Time when the first image is painted.
-  base::Optional<base::TimeDelta> first_image_paint;
-  // Time when the first contentful thing (image, text, etc.) is painted.
-  base::Optional<base::TimeDelta> first_contentful_paint;
-
-  // Time that the document's parser started and stopped parsing main resource
-  // content.
-  base::Optional<base::TimeDelta> parse_start;
-  base::Optional<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. Note that this
-  // value may be updated multiple times during the period between parse_start
-  // and parse_stop.
-  base::Optional<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 this value may be
-  // updated multiple times during the period between parse_start and
-  // parse_stop. 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::Optional<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().
+// Fields are defined in the header page_load_timing_fields.h, so we have a
+// single common definition of fields that can be reused here, in operator==,
+// and in IsEmpty.
+
+#define PAGE_LOAD_TIMING_TIME_DELTA_FIELD(field_name) \
+  base::Optional<base::TimeDelta> field_name;
+#include "chrome/common/page_load_metrics/page_load_timing_fields.h"
+#undef PAGE_LOAD_TIMING_TIME_DELTA_FIELD
 };
 
 struct PageLoadMetadata {