Separate repaint and layout requirements of StyleDifference (Step 1)

Source/core/rendering/RenderObject.cpp

Index: Source/core/rendering/RenderObject.cpp
diff --git a/Source/core/rendering/RenderObject.cpp b/Source/core/rendering/RenderObject.cpp
index 63346d4f89457c81cfbbebc152ad939841139841..91a0a7f823764ddbe58f363ed3d2b1c72b013926 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -1850,57 +1850,59 @@ void RenderObject::handleDynamicFloatPositionChange()
     }
 }
 
-StyleDifference RenderObject::adjustStyleDifference(StyleDifference diff, unsigned contextSensitiveProperties) const
+StyleDifference RenderObject::adjustStyleDifference(StyleDifference diff) const
 {
     // FIXME: The calls to hasDirectReasonsForCompositing are using state that may not be up to date.
     DisableCompositingQueryAsserts disabler;
 
-    if (contextSensitiveProperties & ContextSensitivePropertyTransform && isSVG())
-        diff = StyleDifferenceLayout;
+    if (diff.transformChanged() && isSVG())
+        diff.setNeedsFullLayout();
 
     // If transform changed, and the layer does not paint into its own separate backing, then we need to repaint.
-    if (contextSensitiveProperties & ContextSensitivePropertyTransform  && diff <= StyleDifferenceRepaintLayer) {
+    if (diff.transformChanged() && !diff.needsLayout()) {
         // Text nodes share style with their parents but transforms don't apply to them,
         // hence the !isText() check.
         if (!isText() && (!hasLayer() || !toRenderLayerModelObject(this)->layer()->hasDirectReasonsForCompositing()))
-            diff = StyleDifferenceRepaintLayer;
-        else if (diff < StyleDifferenceRecompositeLayer)
-            diff = StyleDifferenceRecompositeLayer;
+            diff.setNeedsRepaintLayer();
+        else
+            diff.setNeedsRecompositeLayer();
     }
 
     // If opacity or filters changed, and the layer does not paint into its own separate backing, then we need to repaint (also
     // ignoring text nodes)
-    if (contextSensitiveProperties & ContextSensitivePropertyOpacity && diff <= StyleDifferenceRepaintLayer) {
+    if (diff.opacityChanged() && !diff.needsLayout()) {
         if (!isText() && (!hasLayer() || !toRenderLayerModelObject(this)->layer()->hasDirectReasonsForCompositing()))
-            diff = StyleDifferenceRepaintLayer;
-        else if (diff < StyleDifferenceRecompositeLayer)
-            diff = StyleDifferenceRecompositeLayer;
+            diff.setNeedsRepaintLayer();
+        else
+            diff.setNeedsRecompositeLayer();
     }
 
-    if ((contextSensitiveProperties & ContextSensitivePropertyFilter) && hasLayer() && diff <= StyleDifferenceRepaintLayer) {
+    if (diff.filterChanged() && hasLayer() && !diff.needsLayout()) {
         RenderLayer* layer = toRenderLayerModelObject(this)->layer();
         if (!layer->hasDirectReasonsForCompositing() || layer->paintsWithFilters())
-            diff = StyleDifferenceRepaintLayer;
-        else if (diff < StyleDifferenceRecompositeLayer)
-            diff = StyleDifferenceRecompositeLayer;
+            diff.setNeedsRepaintLayer();
+        else
+            diff.setNeedsRecompositeLayer();
     }
 
-    if ((contextSensitiveProperties & ContextSensitivePropertyTextOrColor) && diff < StyleDifferenceRepaint
+    if (diff.textOrColorChanged() && !diff.needsRepaint() && !diff.needsLayout()
         && hasImmediateNonWhitespaceTextChildOrPropertiesDependentOnColor())
-        diff = StyleDifferenceRepaint;
+        diff.setNeedsRepaintObject();
 
     // The answer to layerTypeRequired() for plugins, iframes, and canvas can change without the actual
     // style changing, since it depends on whether we decide to composite these elements. When the
     // layer status of one of these elements changes, we need to force a layout.
-    if (diff == StyleDifferenceEqual && style() && isLayerModelObject()) {
+    if (diff.hasNoChange() && style() && isLayerModelObject()) {
         bool requiresLayer = toRenderLayerModelObject(this)->layerTypeRequired() != NoLayer;
         if (hasLayer() != requiresLayer)
-            diff = StyleDifferenceLayout;
+            diff.setNeedsFullLayout();
     }
 
     // If we have no layer(), just treat a RepaintLayer hint as a normal Repaint.
-    if (diff == StyleDifferenceRepaintLayer && !hasLayer())
-        diff = StyleDifferenceRepaint;
+    if (diff.needsRepaintLayer() && !hasLayer()) {
+        diff.resetNeedsRepaint();
+        diff.setNeedsRepaintObject();
+    }
 
     return diff;
 }
@@ -1964,12 +1966,11 @@ void RenderObject::setStyle(PassRefPtr<RenderStyle> style)
         return;
     }
 
-    StyleDifference diff = StyleDifferenceEqual;
-    unsigned contextSensitiveProperties = ContextSensitivePropertyNone;
+    StyleDifference diff;
     if (m_style)
-        diff = m_style->visualInvalidationDiff(*style, contextSensitiveProperties);
+        diff = m_style->visualInvalidationDiff(*style);
 
-    diff = adjustStyleDifference(diff, contextSensitiveProperties);
+    diff = adjustStyleDifference(diff);
 
     styleWillChange(diff, *style);
 
@@ -1997,23 +1998,23 @@ void RenderObject::setStyle(PassRefPtr<RenderStyle> style)
 
     // Now that the layer (if any) has been updated, we need to adjust the diff again,
     // check whether we should layout now, and decide if we need to repaint.
-    StyleDifference updatedDiff = adjustStyleDifference(diff, contextSensitiveProperties);
+    StyleDifference updatedDiff = adjustStyleDifference(diff);
 
-    if (diff <= StyleDifferenceLayoutPositionedMovementOnly) {
-        if (updatedDiff == StyleDifferenceLayout)
+    if (!diff.needsFullLayout()) {
+        if (updatedDiff.needsFullLayout())
             setNeedsLayoutAndPrefWidthsRecalc();
-        else if (updatedDiff == StyleDifferenceLayoutPositionedMovementOnly)
+        else if (updatedDiff.needsPositionedMovementLayoutOnly())
             setNeedsPositionedMovementLayout();
     }
 
-    if (contextSensitiveProperties & ContextSensitivePropertyTransform && !needsLayout()) {
+    if (diff.transformChanged() && !needsLayout()) {
         if (RenderBlock* container = containingBlock())
             container->setNeedsOverflowRecalcAfterStyleChange();
         if (isBox())
             toRenderBox(this)->updateLayerTransform();
     }
 
-    if (updatedDiff == StyleDifferenceRepaint || updatedDiff == StyleDifferenceRepaintLayer) {
+    if (updatedDiff.needsRepaint()) {
         // Do a repaint with the new style now, e.g., for example if we go from
         // not having an outline to having an outline.
         repaint();
@@ -2047,13 +2048,13 @@ void RenderObject::styleWillChange(StyleDifference diff, const RenderStyle& newS
                     layer->setHasVisibleContent();
                 } else if (layer->hasVisibleContent() && (this == layer->renderer() || layer->renderer()->style()->visibility() != VISIBLE)) {
                     layer->dirtyVisibleContentStatus();
-                    if (diff > StyleDifferenceRepaintLayer)
+                    if (diff.needsLayout())
                         repaint();
                 }
             }
         }
 
-        if (m_parent && diff == StyleDifferenceRepaint)
+        if (m_parent && diff.needsRepaintObjectOnly())
             repaint();
         if (isFloating() && (m_style->floating() != newStyle.floating()))
             // For changes in float styles, we need to conceivably remove ourselves
@@ -2070,12 +2071,13 @@ void RenderObject::styleWillChange(StyleDifference diff, const RenderStyle& newS
 
         // Clearing these bits is required to avoid leaving stale renderers.
         // FIXME: We shouldn't need that hack if our logic was totally correct.
-        if (diff == StyleDifferenceLayout || diff == StyleDifferenceLayoutPositionedMovementOnly) {
+        if (diff.needsFullLayout() || diff.needsPositionedMovementLayoutOnly()) {
             setFloating(false);
             clearPositionedState();
         }
-    } else
+    } else {
         s_affectsParentBlock = false;
+    }
 
     if (view()->frameView()) {
         bool shouldBlitOnFixedBackgroundImage = false;
@@ -2143,7 +2145,7 @@ void RenderObject::styleDidChange(StyleDifference diff, const RenderStyle* oldSt
     if (!m_parent)
         return;
 
-    if (diff == StyleDifferenceLayout) {
+    if (diff.needsFullLayout()) {
         RenderCounter::rendererStyleChanged(*this, oldStyle, m_style.get());
 
         // If the object already needs layout, then setNeedsLayout won't do
@@ -2158,10 +2160,10 @@ void RenderObject::styleDidChange(StyleDifference diff, const RenderStyle* oldSt
         if (needsOverflowRecalcAfterStyleChange() && oldStyle->position() != m_style->position())
             markContainingBlocksForOverflowRecalc();
 
-        if (diff == StyleDifferenceLayout)
-            setNeedsLayoutAndPrefWidthsRecalc();
-    } else if (diff == StyleDifferenceLayoutPositionedMovementOnly)
+        setNeedsLayoutAndPrefWidthsRecalc();
+    } else if (diff.needsPositionedMovementLayoutOnly()) {
         setNeedsPositionedMovementLayout();
+    }
 
     // Don't check for repaint here; we need to wait until the layer has been
     // updated by subclasses before we know if we have to repaint (in setStyle()).