Revert of Teach ScriptRunner how to yield and post on loading task queue

Source/core/dom/ScriptRunner.cpp

Index: Source/core/dom/ScriptRunner.cpp
diff --git a/Source/core/dom/ScriptRunner.cpp b/Source/core/dom/ScriptRunner.cpp
index 75d29b3bc94ed9af13efcc9a8167c52df00ec2dd..88ed1e1c360659213e8affaf7f2ffebd37670c3f 100644
--- a/Source/core/dom/ScriptRunner.cpp
+++ b/Source/core/dom/ScriptRunner.cpp
@@ -30,14 +30,12 @@
 #include "core/dom/Element.h"
 #include "core/dom/ScriptLoader.h"
 #include "platform/heap/Handle.h"
-#include "platform/scheduler/Scheduler.h"
-#include "wtf/Functional.h"
 
 namespace blink {
 
 ScriptRunner::ScriptRunner(Document* document)
     : m_document(document)
-    , m_executeScriptsTaskFactory(WTF::bind(&ScriptRunner::executeScripts, this))
+    , m_timer(this, &ScriptRunner::timerFired)
 {
     ASSERT(document);
 }
@@ -79,13 +77,13 @@
 
 void ScriptRunner::suspend()
 {
-    m_executeScriptsTaskFactory.cancel();
+    m_timer.stop();
 }
 
 void ScriptRunner::resume()
 {
     if (hasPendingScripts())
-        postTaskIfOneIsNotAlreadyInFlight();
+        m_timer.startOneShot(0, FROM_HERE);
 }
 
 void ScriptRunner::notifyScriptReady(ScriptLoader* scriptLoader, ExecutionType executionType)
@@ -101,7 +99,7 @@
         ASSERT(!m_scriptsToExecuteInOrder.isEmpty());
         break;
     }
-    postTaskIfOneIsNotAlreadyInFlight();
+    m_timer.startOneShot(0, FROM_HERE);
 }
 
 void ScriptRunner::notifyScriptLoadError(ScriptLoader* scriptLoader, ExecutionType executionType)
@@ -155,52 +153,26 @@
     }
 }
 
-void ScriptRunner::executeScripts()
+void ScriptRunner::timerFired(Timer<ScriptRunner>* timer)
 {
+    ASSERT_UNUSED(timer, timer == &m_timer);
+
     RefPtrWillBeRawPtr<Document> protect(m_document.get());
 
-    // New scripts are always appended to m_scriptsToExecuteSoon and m_scriptsToExecuteInOrder (never prepended)
-    // so as long as we keep track of the current totals, we can ensure the order of execution if new scripts
-    // are added while executing the current ones.
-    // NOTE a yield followed by a notifyScriptReady(... ASYNC_EXECUTION) will result in that script executing
-    // before any pre-existing ScriptsToExecuteInOrder.
-    size_t numScriptsToExecuteSoon = m_scriptsToExecuteSoon.size();
-    size_t numScriptsToExecuteInOrder = m_scriptsToExecuteInOrder.size();
-    for (size_t i = 0; i < numScriptsToExecuteSoon; i++) {
-        ASSERT(!m_scriptsToExecuteSoon.isEmpty());
-        m_scriptsToExecuteSoon.takeFirst()->execute();
+    WillBeHeapVector<RawPtrWillBeMember<ScriptLoader> > scriptLoaders;
+    scriptLoaders.swap(m_scriptsToExecuteSoon);
+
+    size_t numInOrderScriptsToExecute = 0;
+    for (; numInOrderScriptsToExecute < m_scriptsToExecuteInOrder.size() && m_scriptsToExecuteInOrder[numInOrderScriptsToExecute]->isReady(); ++numInOrderScriptsToExecute)
+        scriptLoaders.append(m_scriptsToExecuteInOrder[numInOrderScriptsToExecute]);
+    if (numInOrderScriptsToExecute)
+        m_scriptsToExecuteInOrder.remove(0, numInOrderScriptsToExecute);
+
+    size_t size = scriptLoaders.size();
+    for (size_t i = 0; i < size; ++i) {
+        scriptLoaders[i]->execute();
         m_document->decrementLoadEventDelayCount();
-        if (yieldForHighPriorityWork())
-            return;
     }
-
-    for (size_t i = 0; i < numScriptsToExecuteInOrder; i++) {
-        ASSERT(!m_scriptsToExecuteInOrder.isEmpty());
-        if (!m_scriptsToExecuteInOrder.first()->isReady())
-            break;
-        m_scriptsToExecuteInOrder.takeFirst()->execute();
-        m_document->decrementLoadEventDelayCount();
-        if (yieldForHighPriorityWork())
-            return;
-    }
-}
-
-bool ScriptRunner::yieldForHighPriorityWork()
-{
-    if (!Scheduler::shared()->shouldYieldForHighPriorityWork())
-        return false;
-
-    postTaskIfOneIsNotAlreadyInFlight();
-    return true;
-}
-
-void ScriptRunner::postTaskIfOneIsNotAlreadyInFlight()
-{
-    if (m_executeScriptsTaskFactory.isPending())
-        return;
-
-    // FIXME: Rename task() so that it's obvious it cancels any pending task.
-    Scheduler::shared()->postLoadingTask(FROM_HERE, m_executeScriptsTaskFactory.task());
 }
 
 void ScriptRunner::trace(Visitor* visitor)