Revert of Script blocking resources tracking should be only done by Document::isScriptExecutionReady

third_party/WebKit/Source/core/html/parser/HTMLScriptRunner.cpp

Index: third_party/WebKit/Source/core/html/parser/HTMLScriptRunner.cpp
diff --git a/third_party/WebKit/Source/core/html/parser/HTMLScriptRunner.cpp b/third_party/WebKit/Source/core/html/parser/HTMLScriptRunner.cpp
index 8fc126133bdaa508cac8d037ad42b5ac7997b00b..07cb059cc5930396fb017ad97bd02bf2314095af 100644
--- a/third_party/WebKit/Source/core/html/parser/HTMLScriptRunner.cpp
+++ b/third_party/WebKit/Source/core/html/parser/HTMLScriptRunner.cpp
@@ -154,7 +154,8 @@
     : m_reentryPermit(reentryPermit),
       m_document(document),
       m_host(host),
-      m_parserBlockingScript(PendingScript::create(nullptr, nullptr)) {
+      m_parserBlockingScript(PendingScript::create(nullptr, nullptr)),
+      m_hasScriptsWaitingForResources(false) {
   ASSERT(m_host);
   ThreadState::current()->registerPreFinalizer(this);
 }
@@ -182,17 +183,18 @@
   // detached.
 }
 
-bool HTMLScriptRunner::isPendingScriptReady() {
-  if (!m_document->isScriptExecutionReady())
+bool HTMLScriptRunner::isPendingScriptReady(const PendingScript* script) {
+  m_hasScriptsWaitingForResources = !m_document->isScriptExecutionReady();
+  if (m_hasScriptsWaitingForResources)
     return false;
-  return m_parserBlockingScript->isReady();
+  return script->isReady();
 }
 
 void HTMLScriptRunner::executeParsingBlockingScript() {
-  DCHECK(m_document);
-  DCHECK(!isExecutingScript());
-  DCHECK(m_document->isScriptExecutionReady());
-  DCHECK(isPendingScriptReady());
+  ASSERT(m_document);
+  ASSERT(!isExecutingScript());
+  ASSERT(m_document->isScriptExecutionReady());
+  ASSERT(isPendingScriptReady(m_parserBlockingScript.get()));
 
   InsertionPointRecord insertionPointRecord(m_host->inputStream());
   executePendingScriptAndDispatchEvent(m_parserBlockingScript.get(),
@@ -213,9 +215,10 @@
   if (!isExecutingScript()) {
     Microtask::performCheckpoint(V8PerIsolateData::mainThreadIsolate());
     if (pendingScriptType == ScriptStreamer::ParsingBlocking) {
+      m_hasScriptsWaitingForResources = !m_document->isScriptExecutionReady();
       // The parser cannot be unblocked as a microtask requested another
       // resource
-      if (!m_document->isScriptExecutionReady())
+      if (m_hasScriptsWaitingForResources)
         return;
     }
   }
@@ -370,7 +373,8 @@
 }
 
 void HTMLScriptRunner::executeParsingBlockingScripts() {
-  while (hasParserBlockingScript() && isPendingScriptReady())
+  while (hasParserBlockingScript() &&
+         isPendingScriptReady(m_parserBlockingScript.get()))
     executeParsingBlockingScript();
 }
 
@@ -386,6 +390,9 @@
 void HTMLScriptRunner::executeScriptsWaitingForResources() {
   TRACE_EVENT0("blink", "HTMLScriptRunner::executeScriptsWaitingForResources");
   ASSERT(m_document);
+  // Callers should check hasScriptsWaitingForResources() before calling
+  // to prevent parser or script re-entry during </style> parsing.
+  ASSERT(hasScriptsWaitingForResources());
   ASSERT(!isExecutingScript());
   ASSERT(m_document->isScriptExecutionReady());
   executeParsingBlockingScripts();