Add StyleChangeState to get rid of a bunch of static state in the render tree.

Source/WebCore/rendering/RenderBox.cpp

Index: Source/WebCore/rendering/RenderBox.cpp
diff --git a/Source/WebCore/rendering/RenderBox.cpp b/Source/WebCore/rendering/RenderBox.cpp
index f93b1474b8a07a98d633f50a3e118ec98b8473d5..dbcbf4f8030a1ac7134f1b79e9b101ba85e65b13 100644
--- a/Source/WebCore/rendering/RenderBox.cpp
+++ b/Source/WebCore/rendering/RenderBox.cpp
@@ -91,8 +91,6 @@ static OverrideSizeMap* gOverrideContainingBlockLogicalWidthMap = 0;
 static const int autoscrollBeltSize = 20;
 static const unsigned backgroundObscurationTestMaxDepth = 4;
 
-bool RenderBox::s_hadOverflowClip = false;
-
 static bool skipBodyBackground(const RenderBox* bodyElementRenderer)
 {
     ASSERT(bodyElementRenderer->isBody());
@@ -210,9 +208,9 @@ void RenderBox::removeFloatingOrPositionedChildFromBlockLists()
         RenderBlock::removePositionedObject(this);
 }
 
-void RenderBox::styleWillChange(StyleDifference diff, const RenderStyle* newStyle)
+void RenderBox::styleWillChange(StyleDifference diff, const RenderStyle* newStyle, StyleChangeState& state)
 {
-    s_hadOverflowClip = hasOverflowClip();
+    state.hadOverflowClip = hasOverflowClip();
 
     RenderStyle* oldStyle = style();
     if (oldStyle) {
@@ -242,17 +240,17 @@ void RenderBox::styleWillChange(StyleDifference diff, const RenderStyle* newStyl
     } else if (newStyle && isBody())
         view()->repaint();
 
-    RenderBoxModelObject::styleWillChange(diff, newStyle);
+    RenderBoxModelObject::styleWillChange(diff, newStyle, state);
 }
 
-void RenderBox::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
+void RenderBox::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle, const StyleChangeState& state)
 {
     // Horizontal writing mode definition is updated in RenderBoxModelObject::updateFromStyle,
     // (as part of the RenderBoxModelObject::styleDidChange call below). So, we can safely cache the horizontal
     // writing mode value before style change here.
     bool oldHorizontalWritingMode = isHorizontalWritingMode();
 
-    RenderBoxModelObject::styleDidChange(diff, oldStyle);
+    RenderBoxModelObject::styleDidChange(diff, oldStyle, state);
 
     RenderStyle* newStyle = style();
     if (needsLayout() && oldStyle) {
@@ -344,9 +342,9 @@ void RenderBox::updateExclusionShapeOutsideInfoAfterStyleChange(const ExclusionS
 }
 #endif
 
-void RenderBox::updateFromStyle()
+void RenderBox::updateFromStyle(const StyleChangeState& state)
 {
-    RenderBoxModelObject::updateFromStyle();
+    RenderBoxModelObject::updateFromStyle(state);
 
     RenderStyle* styleToUse = style();
     bool isRootObject = isRoot();
@@ -375,7 +373,7 @@ void RenderBox::updateFromStyle()
         // Check for overflow clip.
         // It's sufficient to just check one direction, since it's illegal to have visible on only one overflow value.
         if (boxHasOverflowClip) {
-            if (!s_hadOverflowClip)
+            if (!state.hadOverflowClip)

[eseidel, 2013/04/05 01:50:36]

Hopefully the repaint tests will catch if we got this wrong.

                 // Erase the overflow
                 repaint();
             setHasOverflowClip();