[SPv2] Disables paint layer culling

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

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/PaintLayerPainter.h"
 
 #include "core/frame/FrameView.h"
 #include "core/frame/Settings.h"
 #include "core/layout/ClipPathOperation.h"
 #include "core/layout/LayoutBlock.h"
@@ skipping 319 matching lines @@
     PaintLayerFragments layerFragments;
     if (shouldPaintContent || shouldPaintSelfOutline || isPaintingOverlayScrollbars) {
         // Collect the fragments. This will compute the clip rectangles and paint offsets for each layer fragment.
         ClipRectsCacheSlot cacheSlot = (paintFlags & PaintLayerUncachedClipRects) ? UncachedClipRects : PaintingClipRects;
         // TODO(trchen): We haven't decided how to handle visual fragmentation with SPv2.
         // Related thread https://groups.google.com/a/chromium.org/forum/#!topic/graphics-dev/81XuWFf-mxM
         if (fragmentPolicy == ForceSingleFragment || RuntimeEnabledFeatures::slimmingPaintV2Enabled())
             m_paintLayer.appendSingleFragmentIgnoringPagination(layerFragments, localPaintingInfo.rootLayer, localPaintingInfo.paintDirtyRect, cacheSlot, IgnoreOverlayScrollbarSize, respectOverflowClip, &offsetFromRoot, localPaintingInfo.subPixelAccumulation);
         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);
             if (!shouldPaintContent)
                 result = MayBeClippedByPaintDirtyRect;
         }
     }
 
     bool selectionOnly = localPaintingInfo.getGlobalPaintFlags() & GlobalPaintSelectionOnly;
 
@@ skipping 57 matching lines @@
         paintChildClippingMaskForFragments(layerFragments, context, localPaintingInfo, paintFlags);
     }
 
     if (subsequenceRecorder)
         m_paintLayer.setPreviousPaintResult(result);
     return result;
 }
 
 bool PaintLayerPainter::needsToClip(const PaintLayerPaintingInfo& localPaintingInfo, const ClipRect& clipRect)
 {
+    // Clipping will be applied by property nodes directly for SPv2.
+    if (RuntimeEnabledFeatures::slimmingPaintV2Enabled())
+        return false;
+
     return clipRect.rect() != localPaintingInfo.paintDirtyRect || clipRect.hasRadius();
 }
 
 bool PaintLayerPainter::atLeastOneFragmentIntersectsDamageRect(PaintLayerFragments& fragments, const PaintLayerPaintingInfo& localPaintingInfo, PaintLayerFlags localPaintFlags, const LayoutPoint& offsetFromRoot)
 {
     if (m_paintLayer.enclosingPaginationLayer())
         return true; // The fragments created have already been found to intersect with the damage rect.
 
     if (&m_paintLayer == localPaintingInfo.rootLayer && (localPaintFlags & PaintLayerPaintingOverflowContents))
         return true;
@@ skipping 367 matching lines @@
     if (!m_paintLayer.containsDirtyOverlayScrollbars())
         return;
 
     PaintLayerPaintingInfo paintingInfo(&m_paintLayer, LayoutRect(enclosingIntRect(damageRect)), paintFlags, LayoutSize());
     paintLayer(context, paintingInfo, PaintLayerPaintingOverlayScrollbars);
 
     m_paintLayer.setContainsDirtyOverlayScrollbars(false);
 }
 
 } // namespace blink