RAL: Eliminate n^2 walk to find repaint containers

Source/core/rendering/RenderBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 1528 matching lines @@
             }
 
             layerRenderer->repaintRectangle(geometry.destRect());
             if (geometry.destRect() == rendererRect)
                 return true;
         }
     }
     return false;
 }
 
-void RenderBox::repaintTreeAfterLayout()
+void RenderBox::repaintTreeAfterLayout(RenderLayerModelObject& repaintContainer)
 {
     // FIXME: Currently only using this logic for RenderBox and its ilk. Ideally, RenderBlockFlows with
     // inline children should track a dirty rect in local coordinates for dirty lines instead of repainting
     // the world.
     // FIXME: We should still be recursing through inline's children, as they can have boxes, but we don't
     // appear to have tests for this?
     // FIXME: SVG should probably also go through this unified repaint system.
 
     ASSERT(RuntimeEnabledFeatures::repaintAfterLayoutEnabled());
     ASSERT(!needsLayout());
 
     if (!shouldCheckForInvalidationAfterLayout())
         return;
 
+    bool establishesNewRepaintContainer = isRepaintContainer();
+    RenderLayerModelObject& newRepaintContainer = *adjustCompositedContainerForSpecialAncestors(establishesNewRepaintContainer ? this : &repaintContainer);
+    // FIXME: This assert should be re-enabled when we move repaint to after compositing update. crbug.com/360286
+    // ASSERT(&newRepaintContainer == containerForRepaint());
+
     const LayoutRect oldRepaintRect = previousRepaintRect();
     const LayoutPoint oldPositionFromRepaintContainer = previousPositionFromRepaintContainer();
-    RenderLayerModelObject* repaintContainer = containerForRepaint();
-    setPreviousRepaintRect(clippedOverflowRectForRepaint(repaintContainer));
-    setPreviousPositionFromRepaintContainer(positionFromRepaintContainer(repaintContainer));
+    setPreviousRepaintRect(clippedOverflowRectForRepaint(&newRepaintContainer));
+    setPreviousPositionFromRepaintContainer(positionFromRepaintContainer(&newRepaintContainer));
 
     // If we are set to do a full repaint that means the RenderView will be
     // invalidated. We can then skip issuing of invalidations for the child
     // renderers as they'll be covered by the RenderView.
     if (view()->doingFullRepaint() && this != view()) {
-        LayoutStateMaintainer statePusher(*this, isTableRow() ? LayoutSize() : locationOffset());
-        RenderObject::repaintTreeAfterLayout();
+        // FIXME: LayoutState should be enabled for other repaint containers than the RenderView. crbug.com/363834
+        if (establishesNewRepaintContainer) {
+            LayoutStateDisabler disabler(*this);
+            RenderObject::repaintTreeAfterLayout(newRepaintContainer);
+        } else {
+            LayoutStateMaintainer statePusher(*this, isTableRow() ? LayoutSize() : locationOffset());
+            RenderObject::repaintTreeAfterLayout(newRepaintContainer);
+        }
         return;
     }
 
     if ((onlyNeededPositionedMovementLayout() && compositingState() != PaintsIntoOwnBacking)
         || (shouldDoFullRepaintIfSelfPaintingLayer()
             && hasLayer()
             && layer()->isSelfPaintingLayer())) {
         setShouldDoFullRepaintAfterLayout(true);
     }
 
     const LayoutRect& newRepaintRect = previousRepaintRect();
     const LayoutPoint& newPositionFromRepaintContainer = previousPositionFromRepaintContainer();
-    bool didFullRepaint = repaintAfterLayoutIfNeeded(containerForRepaint(),
+    bool didFullRepaint = repaintAfterLayoutIfNeeded(&newRepaintContainer,
         shouldDoFullRepaintAfterLayout(), oldRepaintRect, oldPositionFromRepaintContainer, &newRepaintRect, &newPositionFromRepaintContainer);
 
     if (!didFullRepaint)
         repaintOverflowIfNeeded();
 
     // Repaint any scrollbars if there is a scrollable area for this renderer.
     if (enclosingLayer()) {
         if (RenderLayerScrollableArea* area = enclosingLayer()->scrollableArea()) {
             if (area->hasVerticalBarDamage())
                 repaintRectangle(area->verticalBarDamage());
             if (area->hasHorizontalBarDamage())
                 repaintRectangle(area->horizontalBarDamage());
             area->resetScrollbarDamage();
         }
     }
 
-    // FIXME: This concept of a tree walking state for fast lookups should be generalized away from
-    // just layout.
-    // FIXME: Table rows shouldn't be special-cased.
-    LayoutStateMaintainer statePusher(*this, isTableRow() ? LayoutSize() : locationOffset());
-    RenderObject::repaintTreeAfterLayout();
+    // FIXME: LayoutState should be enabled for other repaint containers than the RenderView. crbug.com/363834

[Julien - ping for review, 2014/05/07 17:50:03]

I choked on this line but Levi pointed out that we already disable LayoutState
if repaintContainer != view()

[leviw_travelin_and_unemployed, 2014/05/07 17:58:48]

As we discussed, I have a plan to fix this (which should be full of win), but am
waiting to be able to clean up the crazyness happening in LayoutState that the
old Repaint logic relies on.

+    if (establishesNewRepaintContainer) {
+        LayoutStateDisabler disabler(*this);
+        RenderObject::repaintTreeAfterLayout(newRepaintContainer);
+    } else {
+        // FIXME: This concept of a tree walking state for fast lookups should be generalized away from
+        // just layout.
+        // FIXME: Table rows shouldn't be special-cased.
+        LayoutStateMaintainer statePusher(*this, isTableRow() ? LayoutSize() : locationOffset());
+        RenderObject::repaintTreeAfterLayout(newRepaintContainer);
+    }
 }
 
 bool RenderBox::pushContentsClip(PaintInfo& paintInfo, const LayoutPoint& accumulatedOffset, ContentsClipBehavior contentsClipBehavior)
 {
     if (paintInfo.phase == PaintPhaseBlockBackground || paintInfo.phase == PaintPhaseSelfOutline || paintInfo.phase == PaintPhaseMask)
         return false;
 
     bool isControlClip = hasControlClip();
     bool isOverflowClip = hasOverflowClip() && !layer()->isSelfPaintingLayer();
 
@@ skipping 3049 matching lines @@
         return 0;
 
     if (!layoutState && !flowThreadContainingBlock())
         return 0;
 
     RenderBlock* containerBlock = containingBlock();
     return containerBlock->offsetFromLogicalTopOfFirstPage() + logicalTop();
 }
 
 } // namespace WebCore