Instrument parser blocking script execution time.

chrome/browser/page_load_metrics/observers/core_page_load_metrics_observer.cc

Index: chrome/browser/page_load_metrics/observers/core_page_load_metrics_observer.cc
diff --git a/chrome/browser/page_load_metrics/observers/core_page_load_metrics_observer.cc b/chrome/browser/page_load_metrics/observers/core_page_load_metrics_observer.cc
index 4bfceb1be9cea2e34bbb2e124a01fc4de54ca348..4f6e6fd6e0939079c5332f6935b77a9222f9dcc1 100644
--- a/chrome/browser/page_load_metrics/observers/core_page_load_metrics_observer.cc
+++ b/chrome/browser/page_load_metrics/observers/core_page_load_metrics_observer.cc
@@ -132,6 +132,15 @@ const char kHistogramParseBlockedOnScriptLoadDocumentWrite[] =
 const char kBackgroundHistogramParseBlockedOnScriptLoadDocumentWrite[] =
     "PageLoad.ParseTiming.ParseBlockedOnScriptLoadFromDocumentWrite."
     "Background";
+const char kHistogramParseBlockedOnScriptExecution[] =
+    "PageLoad.ParseTiming.ParseBlockedOnScriptExecution";
+const char kBackgroundHistogramParseBlockedOnScriptExecution[] =
+    "PageLoad.ParseTiming.ParseBlockedOnScriptExecution.Background";

[Charlie Harrison, 2016/09/07 14:57:37]

I wonder if we can hold off on adding bg histograms until we know we need them?

[Bryan McQuade, 2016/09/07 18:26:09]

I like to have them just so I can understand the ratio of events that happen for
fg/bg pages. If for instance 90% of events happen for pages that are
backgrounded, that's important to know. The distributions are less interesting
but can be useful. I think bg histograms are worth adding for the core
histograms, but optional / not needed for the client histograms.

[Charlie Harrison, 2016/09/07 18:32:50]

If you truly only care about ratio of total events then can't these be trivially
replaced with the parse duration BG histograms? I just worry that we're adding
so many histograms we'll never end up looking at.

[Bryan McQuade, 2016/09/07 23:07:59]

Yeah, you're right - we should get the same counts for parseduration.background,
so we don't need this. Removed.

+const char kHistogramParseBlockedOnScriptExecutionDocumentWrite[] =
+    "PageLoad.ParseTiming.ParseBlockedOnScriptExecutionFromDocumentWrite";
+const char kBackgroundHistogramParseBlockedOnScriptExecutionDocumentWrite[] =
+    "PageLoad.ParseTiming.ParseBlockedOnScriptExecutionFromDocumentWrite."
+    "Background";
 
 const char kHistogramFirstContentfulPaintNoStore[] =
     "PageLoad.PaintTiming.NavigationToFirstContentfulPaint.NoStore";
@@ -455,6 +464,13 @@ void CorePageLoadMetricsObserver::OnParseStop(
         internal::kHistogramParseBlockedOnScriptLoadDocumentWrite,
         timing.parse_blocked_on_script_load_from_document_write_duration
             .value());
+    PAGE_LOAD_HISTOGRAM(
+        internal::kHistogramParseBlockedOnScriptExecution,
+        timing.parse_blocked_on_script_execution_duration.value());
+    PAGE_LOAD_HISTOGRAM(
+        internal::kHistogramParseBlockedOnScriptExecutionDocumentWrite,
+        timing.parse_blocked_on_script_execution_from_document_write_duration
+            .value());
 
     int total_requests = info.num_cache_requests + info.num_network_requests;
     if (total_requests) {
@@ -477,7 +493,6 @@ void CorePageLoadMetricsObserver::OnParseStop(
             parse_duration);
       }
     }
-
   } else {
     PAGE_LOAD_HISTOGRAM(internal::kBackgroundHistogramParseDuration,
                         parse_duration);
@@ -487,6 +502,14 @@ void CorePageLoadMetricsObserver::OnParseStop(
         internal::kBackgroundHistogramParseBlockedOnScriptLoadDocumentWrite,
         timing.parse_blocked_on_script_load_from_document_write_duration
             .value());
+    PAGE_LOAD_HISTOGRAM(
+        internal::kBackgroundHistogramParseBlockedOnScriptExecution,
+        timing.parse_blocked_on_script_execution_duration.value());
+    PAGE_LOAD_HISTOGRAM(
+        internal::
+            kBackgroundHistogramParseBlockedOnScriptExecutionDocumentWrite,
+        timing.parse_blocked_on_script_execution_from_document_write_duration
+            .value());
   }
 }