Separate repaint and layout requirements of StyleDifference (Step 4)

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 ae4ff3f494dee88d0c320c3a728fbeaddda6dd3f..be2db5e0756a456b6c0471a404d900ea5c18efe3 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -1878,7 +1878,7 @@ StyleDifference RenderObject::adjustStyleDifference(StyleDifference diff, unsign
         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.needsLayout()) {
+    if (contextSensitiveProperties & ContextSensitivePropertyTransform) {
         // 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()))
@@ -2025,7 +2025,7 @@ void RenderObject::setStyle(PassRefPtr<RenderStyle> style)
 
     if (!diff.needsFullLayout()) {
         if (updatedDiff.needsFullLayout())
-            setNeedsLayoutAndPrefWidthsRecalc();
+            setNeedsLayoutAndPrefWidthsRecalcWithoutForcingFullRepaint();
         else if (updatedDiff.needsPositionedMovementLayout())
             setNeedsPositionedMovementLayout();
     }
@@ -2037,14 +2037,13 @@ void RenderObject::setStyle(PassRefPtr<RenderStyle> style)
             toRenderBox(this)->updateLayerTransform();
     }
 
-    // FIXME: The !needsFullLayout() check is temporary to keep the original StyleDifference
-    // behavior that we did't repaint here on StyleDifferenceLayout.
-    // In the next steps we will not always repaint on selfNeedsLayout(), and should force
-    // repaint here if needsRepaint is set.
-    if (updatedDiff.needsRepaint() && !updatedDiff.needsFullLayout()) {
-        // 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();
+    if (updatedDiff.needsRepaint()) {
+        // Repaint with the new style, e.g., for example if we go from not having
+        // an outline to having an outline.
+        if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled() && needsLayout())

[Julien - ping for review, 2014/05/12 15:08:46]

Ideally we would want any direct repaint calls to just disappear with
repaint-after-layout. This means that this should be a FIXME:

// FIXME: We will want to migrate all repaint() calls to repaint-after-layout,
probably by setting / propagating the shouldDoFullRepaintAfterLayout boolean.

[Xianzhu, 2014/05/12 21:31:51]

Don't we still need repaint() on repaint-only (no layout) style change?

[Julien - ping for review, 2014/05/20 16:33:30]

We do indeed. However we could make those use repaint-after-layout (which we
should rename at that point). This is a mid-term goal.

+            setShouldDoFullRepaintAfterLayout(true);
+        else
+            repaint();
     }
 }
 
@@ -2081,12 +2080,12 @@ void RenderObject::styleWillChange(StyleDifference diff, const RenderStyle& newS
             }
         }
 
-        // FIXME: The !needsFullLayout() check is temporary to keep the original StyleDifference
-        // behavior that we did't repaint here on StyleDifferenceLayout.
-        // In the next steps we will not always repaint on selfNeedsLayout(), and should force
-        // repaint here if needsRepaintObject is set.
-        if (m_parent && diff.needsRepaintObject() && !diff.needsFullLayout())
-            repaint();
+        if (m_parent && diff.needsRepaintObject()) {
+            if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled() && diff.needsLayout())

[Julien - ping for review, 2014/05/12 15:08:46]

Same comment.

+                setShouldDoFullRepaintAfterLayout(true);
+            else
+                repaint();
+        }
 
         if (isFloating() && (m_style->floating() != newStyle.floating()))
             // For changes in float styles, we need to conceivably remove ourselves
@@ -2193,7 +2192,7 @@ void RenderObject::styleDidChange(StyleDifference diff, const RenderStyle* oldSt
             markContainingBlocksForOverflowRecalc();
 
         if (diff.needsFullLayout())
-            setNeedsLayoutAndPrefWidthsRecalc();
+            setNeedsLayoutAndPrefWidthsRecalcWithoutForcingFullRepaint();
     } else if (diff.needsPositionedMovementLayout())
         setNeedsPositionedMovementLayout();