SPv2: Use GeometryMapper to implement PaintLayerClipper.

third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp b/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
index 86176fa7819076bb8bebf5db97cc9b96570ad85a..6e5c18b8e4ecaa8a0de904a10e5ea07a235ce7d1 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
@@ -235,11 +235,13 @@ static bool shouldRepaintSubsequence(PaintLayer& paintLayer, const PaintLayerPai
         needsRepaint = true;
 
     // Repaint if layer's clip changes.
-    ClipRects& clipRects = paintLayer.clipper().paintingClipRects(paintingInfo.rootLayer, respectOverflowClip, subpixelAccumulation);
-    ClipRects* previousClipRects = paintLayer.previousPaintingClipRects();
-    if (!needsRepaint && &clipRects != previousClipRects && (!previousClipRects || clipRects != *previousClipRects))
-        needsRepaint = true;
-    paintLayer.setPreviousPaintingClipRects(clipRects);
+    if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
+        ClipRects& clipRects = paintLayer.clipper().paintingClipRects(paintingInfo.rootLayer, respectOverflowClip, subpixelAccumulation);
+        ClipRects* previousClipRects = paintLayer.previousPaintingClipRects();
+        if (!needsRepaint && &clipRects != previousClipRects && (!previousClipRects || clipRects != *previousClipRects))
+            needsRepaint = true;
+        paintLayer.setPreviousPaintingClipRects(clipRects);
+    }
 
     // Repaint if previously the layer might be clipped by paintDirtyRect and paintDirtyRect changes.
     if (!needsRepaint && paintLayer.previousPaintResult() == PaintLayerPainter::MayBeClippedByPaintDirtyRect && paintLayer.previousPaintDirtyRect() != paintingInfo.paintDirtyRect)
@@ -345,15 +347,6 @@ PaintLayerPainter::PaintResult PaintLayerPainter::paintLayerContents(GraphicsCon
         else
             m_paintLayer.collectFragments(layerFragments, localPaintingInfo.rootLayer, localPaintingInfo.paintDirtyRect, cacheSlot, IgnoreOverlayScrollbarSize, respectOverflowClip, &offsetFromRoot, localPaintingInfo.subPixelAccumulation);
 
-        // TODO(trchen): Needs to adjust cull rect between transform spaces. https://crbug.com/593596
-        // Disables layer culling for SPv2 for now because the space of the cull rect doesn't match
-        // the space we paint in. Clipping will still be done by clip nodes, so this won't cause
-        // rendering issues, only performance.
-        if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
-            layerFragments[0].backgroundRect = LayoutRect(LayoutRect::infiniteIntRect());
-            layerFragments[0].foregroundRect = LayoutRect(LayoutRect::infiniteIntRect());
-        }
-
         if (shouldPaintContent) {
             // TODO(wangxianzhu): This is for old slow scrolling. Implement similar optimization for slimming paint v2.
             shouldPaintContent = atLeastOneFragmentIntersectsDamageRect(layerFragments, localPaintingInfo, paintFlags, offsetFromRoot);