[WIP] Move layout states into the DocumentLifecycle state machine

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index b4e3993c274ca1c784bec08c5c1de641e2402c42..48b75b5f0e3f35baec0baf4df883a2f1603f30ce 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -435,7 +435,6 @@ Document::Document(const DocumentInit& initializer, DocumentClassFlags documentC
     , m_cssTarget(0)
     , m_loadEventProgress(LoadEventNotRun)
     , m_startTime(currentTime())
-    , m_overMinimumLayoutThreshold(false)
     , m_scriptRunner(ScriptRunner::create(this))
     , m_xmlVersion("1.0")
     , m_xmlStandalone(StandaloneUnspecified)
@@ -1549,9 +1548,23 @@ bool Document::shouldCallRecalcStyleForDocument()
     return needsStyleRecalc() || childNeedsStyleRecalc() || childNeedsDistributionRecalc() || !m_useElementsNeedingUpdate.isEmpty() || childNeedsStyleInvalidation();
 }
 
+bool Document::shouldScheduleStyleRecalc()
+{
+    if (!isActive())
+        return false;
+    if (hasPendingStyleRecalc())
+        return false;
+    if (inStyleRecalc())
+        return false;
+    // InPreLayout will recalc style itself. There's no reason to schedule another recalc.
+    if (m_lifecycle.state() == DocumentLifecycle::InPreLayout)
+        return false;
+    return true;
+}
+
 void Document::scheduleStyleRecalc()
 {
-    if (hasPendingStyleRecalc() || !isActive() || inStyleRecalc() || !shouldScheduleLayout())
+    if (!shouldScheduleStyleRecalc() || !shouldScheduleLayout())
         return;
 
     ASSERT(shouldCallRecalcStyleForDocument());
@@ -1769,7 +1782,7 @@ void Document::recalcStyle(StyleRecalcChange change)
         ASSERT(!needsStyleRecalc());
         ASSERT(!childNeedsStyleRecalc());
         ASSERT(inStyleRecalc());
-        m_lifecycle.advanceTo(DocumentLifecycle::Clean);
+        m_lifecycle.advanceTo(DocumentLifecycle::StyleClean);
     }
 
     InspectorInstrumentation::didRecalculateStyle(cookie);
@@ -2049,7 +2062,7 @@ void Document::attach(const AttachContext& context)
 
     ContainerNode::attach(context);
 
-    m_lifecycle.advanceTo(DocumentLifecycle::Clean);
+    m_lifecycle.advanceTo(DocumentLifecycle::LayoutClean);
 }
 
 void Document::detach(const AttachContext& context)
@@ -2432,14 +2445,12 @@ void Document::implicitClose()
         // Just bail out. Before or during the onload we were shifted to another page.
         // The old i-Bench suite does this. When this happens don't bother painting or laying out.
         m_loadEventProgress = LoadEventCompleted;
-        view()->unscheduleRelayout();
         return;
     }
 
     // We used to force a synchronous display and flush here.  This really isn't
     // necessary and can in fact be actively harmful if pages are loading at a rate of > 60fps
     // (if your platform is syncing flushes and limiting them to 60fps).
-    m_overMinimumLayoutThreshold = true;
     if (!ownerElement() || (ownerElement()->renderer() && !ownerElement()->renderer()->needsLayout())) {
         updateStyleIfNeeded();
 
@@ -2585,19 +2596,7 @@ bool Document::shouldScheduleLayout()
 
 bool Document::shouldParserYieldAgressivelyBeforeScriptExecution()
 {
-    return view() && view()->layoutPending() && !minimumLayoutDelay();
-}
-
-int Document::minimumLayoutDelay()
-{
-    if (m_overMinimumLayoutThreshold)
-        return 0;
-
-    int elapsed = elapsedTime();
-    m_overMinimumLayoutThreshold = elapsed > cLayoutScheduleThreshold;
-
-    // We'll want to schedule the timer to fire at the minimum layout threshold.
-    return max(0, cLayoutScheduleThreshold - elapsed);
+    return view() && view()->layoutPending();
 }
 
 int Document::elapsedTime() const