Fix WebCore.Scripts.ParserBlocking.TimeBetweenLoadedAndCompiled

Source/core/html/parser/HTMLScriptRunner.cpp

 /*
  * Copyright (C) 2010 Google, Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 31 matching lines @@
 
 namespace blink {
 
 using namespace HTMLNames;
 
 HTMLScriptRunner::HTMLScriptRunner(Document* document, HTMLScriptRunnerHost* host)
     : m_document(document)
     , m_host(host)
     , m_scriptNestingLevel(0)
     , m_hasScriptsWaitingForResources(false)
+    , m_parserBlockingScriptAlreadyLoaded(false)
 {
     ASSERT(m_host);
 }
 
 HTMLScriptRunner::~HTMLScriptRunner()
 {
 #if ENABLE(OILPAN)
     // If the document is destructed without having explicitly
     // detached the parser (and this script runner object), perform
     // detach steps now. This will happen if the Document, the parser
@@ skipping 56 matching lines @@
     ASSERT(m_document->isScriptExecutionReady());
     ASSERT(isPendingScriptReady(m_parserBlockingScript));
 
     InsertionPointRecord insertionPointRecord(m_host->inputStream());
     executePendingScriptAndDispatchEvent(m_parserBlockingScript, PendingScriptBlockingParser);
 }
 
 void HTMLScriptRunner::executePendingScriptAndDispatchEvent(PendingScript& pendingScript, PendingScriptType pendingScriptType)
 {
     bool errorOccurred = false;
+    double loadFinishTime = pendingScript.resource() ? pendingScript.resource()->loadFinishTime() : 0;
     ScriptSourceCode sourceCode = pendingScript.getSource(documentURLForScriptExecution(m_document), errorOccurred);
 
     // Stop watching loads before executeScript to prevent recursion if the script reloads itself.
     pendingScript.stopWatchingForLoad(this);
 
     if (!isExecutingScript()) {
         Microtask::performCheckpoint();
         if (pendingScriptType == PendingScriptBlockingParser) {
             m_hasScriptsWaitingForResources = !m_document->isScriptExecutionReady();
             // The parser cannot be unblocked as a microtask requested another resource
             if (m_hasScriptsWaitingForResources)
                 return;
         }
     }
 
     // Clear the pending script before possible rentrancy from executeScript()
     RefPtrWillBeRawPtr<Element> element = pendingScript.releaseElementAndClear();
+    double compilationFinishTime = 0;
     if (ScriptLoader* scriptLoader = toScriptLoaderIfPossible(element.get())) {
         NestingLevelIncrementer nestingLevelIncrementer(m_scriptNestingLevel);
         IgnoreDestructiveWriteCountIncrementer ignoreDestructiveWriteCountIncrementer(m_document);
         if (errorOccurred)
             scriptLoader->dispatchErrorEvent();
         else {
             ASSERT(isExecutingScript());
-            scriptLoader->executeScript(sourceCode);
+            scriptLoader->executeScript(sourceCode, &compilationFinishTime);
             element->dispatchEvent(createScriptLoadEvent());
         }
     }
-    if (sourceCode.resource()) {
-        double timeBetweenLoadedAndCompiledMs = (WTF::monotonicallyIncreasingTime() - sourceCode.resource()->loadFinishTime()) * 1000;
-        const char* histogramName = pendingScriptType == PendingScriptBlockingParser ? "WebCore.Scripts.ParsingBlocking.TimeBetweenLoadedAndCompiled" : "WebCore.Scripts.Deferred.TimeBetweenLoadedAndCompiled";
-        blink::Platform::current()->histogramCustomCounts(histogramName, timeBetweenLoadedAndCompiledMs, 0, 10000, 50);
+    // The exact value doesn't matter; valid time stamps are much bigger than this value.
+    const double epsilon = 1;
+    if (pendingScriptType == PendingScriptBlockingParser && !m_parserBlockingScriptAlreadyLoaded && compilationFinishTime > epsilon && loadFinishTime > epsilon) {
+        blink::Platform::current()->histogramCustomCounts("WebCore.Scripts.ParsingBlocking.TimeBetweenLoadedAndCompiled", (compilationFinishTime - loadFinishTime) * 1000, 0, 10000, 50);
     }
 
     ASSERT(!isExecutingScript());
 }
 
 void HTMLScriptRunner::notifyFinished(Resource* cachedResource)
 {
     m_host->notifyScriptLoaded(cachedResource);
 }
 
@@ skipping 70 matching lines @@
     return true;
 }
 
 void HTMLScriptRunner::requestParsingBlockingScript(Element* element)
 {
     if (!requestPendingScript(m_parserBlockingScript, element))
         return;
 
     ASSERT(m_parserBlockingScript.resource());
 
-    blink::Platform::current()->histogramEnumeration("WebCore.Scripts.ParsingBlocking.AlreadyLoaded", m_parserBlockingScript.resource()->isLoaded() ? 1 : 0, 2);
+    m_parserBlockingScriptAlreadyLoaded = m_parserBlockingScript.resource()->isLoaded();
+    blink::Platform::current()->histogramEnumeration("WebCore.Scripts.ParsingBlocking.AlreadyLoaded", m_parserBlockingScriptAlreadyLoaded ? 1 : 0, 2);
     // We only care about a load callback if resource is not already
     // in the cache. Callers will attempt to run the m_parserBlockingScript
     // if possible before returning control to the parser.
-    if (!m_parserBlockingScript.resource()->isLoaded())
+    if (!m_parserBlockingScriptAlreadyLoaded)
         m_parserBlockingScript.watchForLoad(this);
 }
 
 void HTMLScriptRunner::requestDeferredScript(Element* element)
 {
     PendingScript pendingScript;
     if (!requestPendingScript(pendingScript, element))
         return;
 
     ASSERT(pendingScript.resource());
@@ skipping 62 matching lines @@
 
 void HTMLScriptRunner::trace(Visitor* visitor)
 {
     visitor->trace(m_document);
     visitor->trace(m_host);
     visitor->trace(m_parserBlockingScript);
     visitor->trace(m_scriptsToExecuteAfterParsing);
 }
 
 }