Don't include scroll offset in offsetFromLayoutObject for scrolling contents layers.

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 987 matching lines @@
         m_childClippingMaskLayer->setOffsetFromLayoutObject(toIntSize(overflowClipRect.location()));
     }
 
     bool overflowClipRectOffsetChanged = oldScrollingLayerOffset != m_scrollingLayer->offsetFromLayoutObject();
 
     IntSize scrollSize(layoutBox->scrollWidth(), layoutBox->scrollHeight());
     if (scrollSize != m_scrollingContentsLayer->size() || overflowClipRectOffsetChanged)
         m_scrollingContentsLayer->setNeedsDisplay();
 
     DoubleSize scrollingContentsOffset(overflowClipRect.location().x() - adjustedScrollOffset.width(), overflowClipRect.location().y() - adjustedScrollOffset.height());
-    // The scroll offset change is compared using floating point so that fractional scroll offset
-    // change can be propagated to compositor.
-    if (scrollingContentsOffset != m_scrollingContentsLayer->offsetDoubleFromLayoutObject() || scrollSize != m_scrollingContentsLayer->size()) {
+    // // The scroll offset change is compared using floating point so that fractional scroll offset
+    // // change can be propagated to compositor.

[Xianzhu, 2016/05/31 16:46:27]

Nit: //

[chrishtr, 2016/05/31 16:58:40]

Done.

+    if (scrollingContentsOffset != m_scrollingContentsOffset || scrollSize != m_scrollingContentsLayer->size()) {
         bool coordinatorHandlesOffset = compositor()->scrollingLayerDidChange(&m_owningLayer);
         m_scrollingContentsLayer->setPosition(coordinatorHandlesOffset ? FloatPoint() : FloatPoint(-toFloatSize(adjustedScrollOffset)));
     }
+    m_scrollingContentsOffset = scrollingContentsOffset;
 
     m_scrollingContentsLayer->setSize(FloatSize(scrollSize));
-    // FIXME: The paint offset and the scroll offset should really be separate concepts.
-    m_scrollingContentsLayer->setOffsetDoubleFromLayoutObject(scrollingContentsOffset, GraphicsLayer::DontSetNeedsDisplay);
+    m_scrollingContentsLayer->setOffsetDoubleFromLayoutObject(toIntSize(overflowClipRect.location()), GraphicsLayer::DontSetNeedsDisplay);
 
     if (m_foregroundLayer) {
         if (m_foregroundLayer->size() != m_scrollingContentsLayer->size())
             m_foregroundLayer->setSize(m_scrollingContentsLayer->size());
         m_foregroundLayer->setNeedsDisplay();
         m_foregroundLayer->setOffsetFromLayoutObject(m_scrollingContentsLayer->offsetFromLayoutObject());
     }
 }
 
 void CompositedLayerMapping::updateChildClippingMaskLayerGeometry()
@@ skipping 381 matching lines @@
 }
 
 enum ApplyToGraphicsLayersModeFlags {
     ApplyToLayersAffectedByPreserve3D = (1 << 0),
     ApplyToSquashingLayer = (1 << 1),
     ApplyToScrollbarLayers = (1 << 2),
     ApplyToBackgroundLayer = (1 << 3),
     ApplyToMaskLayers = (1 << 4),
     ApplyToContentLayers = (1 << 5),
     ApplyToChildContainingLayers = (1 << 6), // layers between m_graphicsLayer and children
-    ApplyToAllGraphicsLayers = (ApplyToSquashingLayer | ApplyToScrollbarLayers | ApplyToBackgroundLayer | ApplyToMaskLayers | ApplyToLayersAffectedByPreserve3D | ApplyToContentLayers)
+    ApplyToScrollingContentLayers = (1 << 7),
+    ApplyToAllGraphicsLayers = (ApplyToSquashingLayer | ApplyToScrollbarLayers | ApplyToBackgroundLayer | ApplyToMaskLayers | ApplyToLayersAffectedByPreserve3D | ApplyToContentLayers | ApplyToScrollingContentLayers)
 };
 typedef unsigned ApplyToGraphicsLayersMode;
 
 template <typename Func>
 static void ApplyToGraphicsLayers(const CompositedLayerMapping* mapping, const Func& f, ApplyToGraphicsLayersMode mode)
 {
     ASSERT(mode);
 
     if ((mode & ApplyToLayersAffectedByPreserve3D) && mapping->childTransformLayer())
         f(mapping->childTransformLayer());
     if (((mode & ApplyToLayersAffectedByPreserve3D) || (mode & ApplyToContentLayers)) && mapping->mainGraphicsLayer())
         f(mapping->mainGraphicsLayer());
     if (((mode & ApplyToLayersAffectedByPreserve3D) || (mode & ApplyToChildContainingLayers)) && mapping->clippingLayer())
         f(mapping->clippingLayer());
     if (((mode & ApplyToLayersAffectedByPreserve3D) || (mode & ApplyToChildContainingLayers)) && mapping->scrollingLayer())
         f(mapping->scrollingLayer());
-    if (((mode & ApplyToLayersAffectedByPreserve3D) || (mode & ApplyToContentLayers) || (mode & ApplyToChildContainingLayers)) && mapping->scrollingContentsLayer())
+    if (((mode & ApplyToLayersAffectedByPreserve3D) || (mode & ApplyToContentLayers) || (mode & ApplyToChildContainingLayers) || (mode & ApplyToScrollingContentLayers)) && mapping->scrollingContentsLayer())
         f(mapping->scrollingContentsLayer());
-    if (((mode & ApplyToLayersAffectedByPreserve3D) || (mode & ApplyToContentLayers)) && mapping->foregroundLayer())
+    if (((mode & ApplyToLayersAffectedByPreserve3D) || (mode & ApplyToContentLayers) || (mode & ApplyToScrollingContentLayers)) && mapping->foregroundLayer())
         f(mapping->foregroundLayer());
 
     if ((mode & ApplyToChildContainingLayers) && mapping->childTransformLayer())
         f(mapping->childTransformLayer());
 
     if ((mode & ApplyToSquashingLayer) && mapping->squashingLayer())
         f(mapping->squashingLayer());
 
     if (((mode & ApplyToMaskLayers) || (mode & ApplyToContentLayers)) && mapping->maskLayer())
         f(mapping->maskLayer());
@@ skipping 653 matching lines @@
     // ASSERT(!RuntimeEnabledFeatures::slimmingPaintV2Enabled());
 
     SetContentsNeedsDisplayInRectFunctor functor = {
         enclosingIntRect(LayoutRect(r.location() + m_owningLayer.subpixelAccumulation(), r.size())),
         invalidationReason,
         client
     };
     ApplyToGraphicsLayers(this, functor, ApplyToContentLayers);
 }
 
+void CompositedLayerMapping::setScrollingContentsNeedDisplayInRect(const LayoutRect& r, PaintInvalidationReason invalidationReason, const DisplayItemClient& client)
+{
+    // TODO(wangxianzhu): Enable the following assert after paint invalidation for spv2 is ready.
+    // ASSERT(!RuntimeEnabledFeatures::slimmingPaintV2Enabled());
+
+    SetContentsNeedsDisplayInRectFunctor functor = {
+        enclosingIntRect(LayoutRect(r.location() + m_owningLayer.subpixelAccumulation(), r.size())),
+        invalidationReason,
+        client
+    };
+    ApplyToGraphicsLayers(this, functor, ApplyToScrollingContentLayers);
+}
+
 void CompositedLayerMapping::displayItemClientWasInvalidated(const DisplayItemClient& displayItemClient, PaintInvalidationReason paintInvalidationReason)
 {
     ApplyToGraphicsLayers(this, [&displayItemClient, paintInvalidationReason](GraphicsLayer* layer) {
         layer->displayItemClientWasInvalidated(displayItemClient, paintInvalidationReason);
     }, ApplyToContentLayers);
 }
 
 const GraphicsLayerPaintInfo* CompositedLayerMapping::containingSquashedLayer(const LayoutObject* layoutObject, const Vector<GraphicsLayerPaintInfo>& layers, unsigned maxSquashedLayerIndex)
 {
     for (size_t i = 0; i < layers.size() && i < maxSquashedLayerIndex; ++i) {
@@ skipping 111 matching lines @@
             return IntRect();
         // All squashed layers have the same clip and transform space, so we can use the first squashed layer's
         // layoutObject to map the squashing layer's bounds into viewport space, with offsetFromAnchorLayoutObject
         // to translate squashing layer's bounds into the first squashed layer's space.
         anchorLayoutObject = m_squashedLayers[0].paintLayer->layoutObject();
         offsetFromAnchorLayoutObject = m_squashedLayers[0].offsetFromLayoutObject;
     } else {
         ASSERT(graphicsLayer == m_graphicsLayer || graphicsLayer == m_scrollingContentsLayer);
         anchorLayoutObject = m_owningLayer.layoutObject();
         offsetFromAnchorLayoutObject = graphicsLayer->offsetFromLayoutObject();
+        adjustForCompositedScrolling(graphicsLayer, offsetFromAnchorLayoutObject);
     }
 
     // Start with the bounds of the graphics layer in the space of the anchor LayoutObject.
     FloatRect graphicsLayerBoundsInObjectSpace(graphicsLayerBounds);
     graphicsLayerBoundsInObjectSpace.move(offsetFromAnchorLayoutObject);
     // The object space means including writing mode flip.
     if (anchorLayoutObject->isBox())
         toLayoutBox(anchorLayoutObject)->flipForWritingMode(graphicsLayerBoundsInObjectSpace);
 
     // Now map the bounds to its visible content rect in screen space, including applying clips along the way.
@@ skipping 80 matching lines @@
 LayoutSize CompositedLayerMapping::subpixelAccumulation() const
 {
     return m_owningLayer.subpixelAccumulation();
 }
 
 bool CompositedLayerMapping::needsRepaint(const GraphicsLayer& graphicsLayer) const
 {
     return isScrollableAreaLayer(&graphicsLayer) ? true : m_owningLayer.needsRepaint();
 }
 
+void CompositedLayerMapping::adjustForCompositedScrolling(const GraphicsLayer* graphicsLayer, IntSize& offset) const
+{
+    if (graphicsLayer == m_scrollingContentsLayer.get() || graphicsLayer == m_foregroundLayer.get()) {
+        DoubleSize adjustedScrollOffset = m_owningLayer.getScrollableArea()->adjustedScrollOffset();
+        offset.expand(-adjustedScrollOffset.width(), -adjustedScrollOffset.height());
+    }
+}
+
 void CompositedLayerMapping::paintContents(const GraphicsLayer* graphicsLayer, GraphicsContext& context,
     GraphicsLayerPaintingPhase graphicsLayerPaintingPhase, const IntRect& interestRect) const
 {
     // https://code.google.com/p/chromium/issues/detail?id=343772
     DisableCompositingQueryAsserts disabler;
     // Allow throttling to make sure no painting paths (e.g.,
     // ContentLayerDelegate::paintContents) try to paint throttled content.
     DocumentLifecycle::AllowThrottlingScope allowThrottling(m_owningLayer.layoutObject()->document().lifecycle());
 #if ENABLE(ASSERT)
     // FIXME: once the state machine is ready, this can be removed and we can refer to that instead.
@@ skipping 26 matching lines @@
         || graphicsLayer == m_foregroundLayer.get()
         || graphicsLayer == m_backgroundLayer.get()
         || graphicsLayer == m_maskLayer.get()
         || graphicsLayer == m_childClippingMaskLayer.get()
         || graphicsLayer == m_scrollingContentsLayer.get()) {
 
         GraphicsLayerPaintInfo paintInfo;
         paintInfo.paintLayer = &m_owningLayer;
         paintInfo.compositedBounds = compositedBounds();
         paintInfo.offsetFromLayoutObject = graphicsLayer->offsetFromLayoutObject();
+        adjustForCompositedScrolling(graphicsLayer, paintInfo.offsetFromLayoutObject);
 
         // We have to use the same root as for hit testing, because both methods can compute and cache clipRects.
         doPaintTask(paintInfo, *graphicsLayer, paintLayerFlags, context, interestRect);
     } else if (graphicsLayer == m_squashingLayer.get()) {
         for (size_t i = 0; i < m_squashedLayers.size(); ++i)
             doPaintTask(m_squashedLayers[i], *graphicsLayer, paintLayerFlags, context, interestRect);
     } else if (isScrollableAreaLayer(graphicsLayer)) {
         paintScrollableArea(graphicsLayer, context, interestRect);
     }
     InspectorInstrumentation::didPaint(m_owningLayer.layoutObject()->frame(), graphicsLayer, context, LayoutRect(interestRect));
@@ skipping 206 matching lines @@
     } else if (graphicsLayer == m_scrollingContentsLayer.get()) {
         name = "Scrolling Contents Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink