Add FMP to DataReductionProxy UMA and to Pingback Metrics

components/data_reduction_proxy/core/common/data_reduction_proxy_page_load_timing.h

Index: components/data_reduction_proxy/core/common/data_reduction_proxy_page_load_timing.h
diff --git a/components/data_reduction_proxy/core/common/data_reduction_proxy_page_load_timing.h b/components/data_reduction_proxy/core/common/data_reduction_proxy_page_load_timing.h
index 43aa81be8dc1365d4c7484b37047528cce46cebb..e9b023446fa8584c98d02c69e661e28f54ab985b 100644
--- a/components/data_reduction_proxy/core/common/data_reduction_proxy_page_load_timing.h
+++ b/components/data_reduction_proxy/core/common/data_reduction_proxy_page_load_timing.h
@@ -12,20 +12,22 @@ namespace data_reduction_proxy {
 
 // The timing information that is relevant to the Pageload metrics pingback.
 struct DataReductionProxyPageLoadTiming {
   DataReductionProxyPageLoadTiming(
       const base::Time& navigation_start,
       const base::Optional<base::TimeDelta>& response_start,
       const base::Optional<base::TimeDelta>& load_event_start,
       const base::Optional<base::TimeDelta>& first_image_paint,
       const base::Optional<base::TimeDelta>& first_contentful_paint,
       const base::Optional<base::TimeDelta>&
+          experimental_first_meaningful_paint,
+      const base::Optional<base::TimeDelta>&
           parse_blocked_on_script_load_duration,
       const base::Optional<base::TimeDelta>& parse_stop);
 
   DataReductionProxyPageLoadTiming(
       const DataReductionProxyPageLoadTiming& other);
 
   // Time that the navigation for the associated page was initiated.
   const base::Time navigation_start;
 
   // All TimeDeltas are relative to navigation_start.
@@ -33,19 +35,21 @@ struct DataReductionProxyPageLoadTiming {
   // Time that the first byte of the response is received.
   const base::Optional<base::TimeDelta> response_start;
 
   // Time immediately before the load event is fired.
   const base::Optional<base::TimeDelta> load_event_start;
 
   // Time when the first image is painted.
   const base::Optional<base::TimeDelta> first_image_paint;
   // Time when the first contentful thing (image, text, etc.) is painted.
   const base::Optional<base::TimeDelta> first_contentful_paint;
+  // (Experimental) Time when the page's primary content is painted.
+  const base::Optional<base::TimeDelta> experimental_first_meaningful_paint;
   // Time that parsing was blocked by loading script.
   const base::Optional<base::TimeDelta> parse_blocked_on_script_load_duration;
   // Time when parsing completed.
   const base::Optional<base::TimeDelta> parse_stop;
 };
 
 }  // namespace data_reduction_proxy
 
 #endif  // COMPONENTS_DATA_REDUCTION_PROXY_CORE_COMMON_DATA_REDUCTION_PROXY_PAGE_LOAD_TIMING_H