Record parser blocking time for scripts inserted via doc.write

third_party/WebKit/Source/core/dom/DocumentParserTiming.h

Index: third_party/WebKit/Source/core/dom/DocumentParserTiming.h
diff --git a/third_party/WebKit/Source/core/dom/DocumentParserTiming.h b/third_party/WebKit/Source/core/dom/DocumentParserTiming.h
index 6a2134ee38233c4dea9d13ca6db8c208235c6123..6eef324624492d24e6afe74ca607b34dac7207d3 100644
--- a/third_party/WebKit/Source/core/dom/DocumentParserTiming.h
+++ b/third_party/WebKit/Source/core/dom/DocumentParserTiming.h
@@ -44,9 +44,12 @@ public:
     void markParserDetached();
 
     // Record a duration of time that the parser yielded due to loading a
-    // script, in seconds. This may be called multiple times, once for each time
-    // the parser yields on a script load.
-    void recordParserBlockedOnScriptLoadDuration(double duration);
+    // script, in seconds. scriptInsertedViaDocumentWrite indicates whether the
+    // script causing blocking was inserted via document.write. This may be
+    // called multiple times, once for each time the parser yields on a script
+    // load.
+    void recordParserBlockedOnScriptLoadDuration(
+        double duration, bool scriptInsertedViaDocumentWrite);
 
     // The getters below return monotonically-increasing seconds, or zero if the
     // given parser event has not yet occurred.  See the comments for
@@ -59,6 +62,10 @@ public:
     // recordParseBlockedOnScriptLoadDuration.
     double parserBlockedOnScriptLoadDuration() const { return m_parserBlockedOnScriptLoadDuration; }
 
+    // Returns the sum of all blocking script load durations due to
+    // document.write reported via recordParseBlockedOnScriptLoadDuration.
+    double parserBlockedOnScriptLoadFromDocumentWriteDuration() const { return m_parserBlockedOnScriptLoadFromDocumentWriteDuration; }

[Charlie Harrison, 2016/04/04 21:33:26]

Can you include a comment that this is a lower bound, because the mechanism for
determining if a script was written by document.write sometimes has false
negatives?

[Bryan McQuade, 2016/04/05 15:14:11]

Done.

+
     DECLARE_VIRTUAL_TRACE();
 
 private:
@@ -68,6 +75,7 @@ private:
     double m_parserStart = 0.0;
     double m_parserStop = 0.0;
     double m_parserBlockedOnScriptLoadDuration = 0.0;
+    double m_parserBlockedOnScriptLoadFromDocumentWriteDuration = 0.0;
     bool m_parserDetached = false;
 
     Member<Document> m_document;