Use unified invalidation path for repaint-only style changes

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 9e72e470370fa9960797db03a40b95aec44e7459..24b2766dd754a427a99576d70f130d6ae607b61c 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -1598,7 +1598,7 @@ void RenderObject::invalidateTreeIfNeeded(const PaintInvalidationState& paintInv
 {
     // If we didn't need paint invalidation then our children don't need as well.
     // Skip walking down the tree as everything should be fine below us.
-    if (!shouldCheckForPaintInvalidation())
+    if (!shouldCheckForSelfOrChildPaintInvalidation())
         return;
 
     clearPaintInvalidationState();
@@ -2055,15 +2055,17 @@ void RenderObject::setStyle(PassRefPtr<RenderStyle> style)
             container->setNeedsOverflowRecalcAfterStyleChange();
     }
 
-    if (updatedDiff.needsRepaint()) {
-        // Invalidate paints with the new style, e.g., for example if we go from not having
-        // an outline to having an outline.
-
-        // The paintInvalidationForWholeRenderer() call is needed for non-layout changes to style. See the corresponding
-        // comment in RenderObject::styleWillChange for why.
-        if (needsLayout())
+    // FIXME: Should invalidate whole layer if updatedDiff.needsRepaintLayer(). crbug.com/394050.
+    if (diff.needsRepaintObject() || updatedDiff.needsRepaint()) {
+        // FIXME: For objects that don't save previousPaintInvalidationRect, we still need
+        // to invalidate now because their invalidateTreeIfNeeded won't invalidate themselves.
+        // crbug.com/394133.
+        // FIXME: Test of parentTransformDidChange in RenderSVGModelObject::invalidateTreeIfNeeded()
+        // prevents SVG objects from using unified invalidation for repaint-only style change.
+        // crbug.com/394619.
+        if (needsLayout() || (canSelfInvalidateDuringTreeInvalidation() && !isSVG()))
             setShouldDoFullPaintInvalidation(true);
-        else if (!selfNeedsLayout())
+        else
             paintInvalidationForWholeRenderer();
     }
 }
@@ -2099,12 +2101,14 @@ void RenderObject::styleWillChange(StyleDifference diff, const RenderStyle& newS
             }
         }
 
-        // For style-only changes that need paint invalidation, we currently need to issue a paint invalidation before and after the style
-        // change. The paint invalidation before style change is accomplished here. The paint invalidation after style change is accomplished
-        // in RenderObject::setStyle.
         if (m_parent && diff.needsRepaintObject()) {
-            if (!diff.needsLayout() && !needsLayout())
-                paintInvalidationForWholeRenderer();
+            if (!diff.needsLayout() && !needsLayout()) {
+                // Invalidate before style change.
+                // FIXME: See FIXMEs in setStyle() before calling paintInvalidationForWholeRenderer
+                // for the reason of this paintInvalidationForWholeRenderer.
+                if (!canSelfInvalidateDuringTreeInvalidation() || isSVG())
+                    paintInvalidationForWholeRenderer();
+            }
         }
 
         if (isFloating() && (m_style->floating() != newStyle.floating()))
@@ -3394,6 +3398,17 @@ bool RenderObject::isRelayoutBoundaryForInspector() const
     return objectIsRelayoutBoundary(this);
 }
 
+void RenderObject::setShouldDoFullPaintInvalidation(bool b)

[Julien - ping for review, 2014/07/18 18:49:44]

I really think we should split the setting from the clearing, which would remove
this boolean.

+{
+    m_bitfields.setShouldDoFullPaintInvalidation(b);
+    if (!b)
+        return;
+
+    // Make sure our parent is marked so that the next invalidateTreeIfNeeded can reach this object.
+    for (RenderObject* p = parent(); p && !p->shouldCheckForSelfOrChildPaintInvalidation(); p = p->parent())

[Julien - ping for review, 2014/07/18 18:49:44]

This is wrong for 2 reasons:
- We shouldn't walk the parent tree to invalidate, we should walk the containing
block chain :(
- We may end up calling that function during paintInvalidation (see
RenderBox::invalidateTreeIfNeeded), which will leave renderers marked for
invalidation for the next phase.

+        p->setChildNeedsPaintInvalidation(true);
+}
+
 void RenderObject::clearPaintInvalidationState()
 {
     setShouldDoFullPaintInvalidation(false);
@@ -3403,6 +3418,7 @@ void RenderObject::clearPaintInvalidationState()
     setShouldInvalidateOverflowForPaint(false);
     setLayoutDidGetCalled(false);
     setMayNeedPaintInvalidation(false);
+    setChildNeedsPaintInvalidation(false);
 }
 
 bool RenderObject::isAllowedToModifyRenderTreeStructure(Document& document)