https://bugs.webkit.org/show_bug.cgi?id=101874

Reviewed by Dave Hyatt.

Source/WebCore:

RenderLayer::updateLayerPositions() and updateLayerPositionsAfterScroll() spend a
lot of time in computeRepaintRects(), which does two ancestor tree walks, once
for clippedOverflowRectForRepaint(), and one for outlineBoundsForRepaint().

Eliminate the ancestor tree walk in outlineBoundsForRepaint() by maintaining
a RenderGeometryMap as we traverse the layer tree, and then using it to map
the outline bounds to the repaint container. Replace the hokey cached offsetFromRoot
now that the RenderGeometryMap can do a better job.

The clipped overflow rect cannot be mapped simply, so cannot yet make use of
the geometry map.

Modify the RenderGeometryMap to support mapping to some repaintContainer ancestor.
Add a RenderObject walk that is necessary to detect flipped writing mode blocks.

Pass the RenderGeometryMap as an optional parameter to outlineBoundsForRepaint.

* page/FrameView.cpp:
(WebCore::FrameView::layout): Make a RenderGeometryMap and pass it down
to updateLayerPositions(). For partial layouts, we have to push layers
between the root and the enclosing layer of the layout subtree.
The geometry map used for repainting does not use SnapOffsetForTransforms,
so initialize it explicitly with just the UseTransforms flag.
(WebCore::FrameView::repaintFixedElementsAfterScrolling): Make a RenderGeometryMap
to pass along to updateLayerPositionsAfterScroll().
* rendering/RenderBox.cpp:
(WebCore::RenderBox::outlineBoundsForRepaint): Replace the optional cachedOffsetToRepaintContainer
parameter with an optional RenderGeometryMap, and it use to map the compute rect to
repaintContainer coordinates.
* rendering/RenderBox.h:
* rendering/RenderGeometryMap.cpp:
(WebCore::RenderGeometryMap::RenderGeometryMap): This now has to store the mapping
flags to use, so that its behavior can match that of mapLocalToContainer(). The
pertinent flag is the confusingly named SnapOffsetForTransforms.
(WebCore::RenderGeometryMap::absolutePoint): Call the new mapToContainer() with
a null container.
(WebCore::RenderGeometryMap::absoluteRect): Ditto.
(WebCore::RenderGeometryMap::mapToContainer): Map to the supplied container,
asserting that we found it. Add point- and rect-based mapping methods
akin to the old absoluteRect/absolutePoint.
(WebCore::canMapViaLayer): We need to test for isRenderFlowThread() here too.
(WebCore::RenderGeometryMap::pushMappingsToAncestor): When mapping via
layers, ensure that the RenderView is pushed as the first step.
* rendering/RenderGeometryMap.h:
(RenderGeometryMap):
* rendering/RenderLayer.cpp:
(WebCore::RenderLayer::updateLayerPositionsAfterLayout): New wrapper for updateLayerPositions()
that makes the geometry map.
(WebCore::RenderLayer::updateLayerPositionsAfterScroll): New wrapper for updateLayerPositionsAfterScroll
that makes the geometry map.
(WebCore::RenderLayer::updateLayerPositions): Now takes an optional RenderGeometryMap.
Remove the old offsetFromRoot code. Push and pop layers to/from the geometry map. Use
the geometry map to get the offsetFromRoot as needed by overflow controls. Pass
it to computeRepaintRects().
(WebCore::RenderLayer::computeRepaintRects): Pass the geometry map to outlineBoundsForRepaint().
(WebCore::RenderLayer::updateLayerPositionsAfterScroll): Push and pop to/from the
geometry map, and pass it to computeRepaintRects().
(WebCore::RenderLayer::removeOnlyThisLayer): Remove the offsetFromRootBeforeMove
computation; this could use a geometry map in future if it is shown to be a bottleneck.
* rendering/RenderLayer.h:
(WebCore::RenderLayer::canUseConvertToLayerCoords): It was thought that the isComposited()
was there because the older cached offsetFromRoot logic was sensitive to compositing,
but convertToLayerCoords() is not affected by compositing so this check is not needed,
and actually harmful.
* rendering/RenderLayerCompositor.cpp:
(WebCore::RenderLayerCompositor::OverlapMap::OverlapMap): The geometry map
used for overlap testing should not use SnapOffsetForTransforms, so initialize
it explicitly with just the UseTransforms flag.
* rendering/RenderObject.h:
(WebCore::RenderObject::outlineBoundsForRepaint):
* rendering/svg/RenderSVGModelObject.cpp:
(WebCore::RenderSVGModelObject::outlineBoundsForRepaint):
* rendering/svg/RenderSVGModelObject.h:
(RenderSVGModelObject):

LayoutTests:

In debug, skip tests that assert because of LayoutUnit truncation.

* platform/mac/TestExpectations:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@135025 268f45cc-cd09-0410-ab3c-d52691b4dbfc