Adapt and reland old position sticky implementation

third_party/WebKit/Source/core/layout/compositing/CompositingInputsUpdater.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/layout/compositing/CompositingInputsUpdater.h"
 
+#include "core/frame/FrameView.h"
 #include "core/layout/LayoutBlock.h"
+#include "core/layout/LayoutView.h"
 #include "core/layout/compositing/CompositedLayerMapping.h"
 #include "core/layout/compositing/PaintLayerCompositor.h"
 #include "core/paint/PaintLayer.h"
 #include "platform/TraceEvent.h"
 
 namespace blink {
 
 CompositingInputsUpdater::CompositingInputsUpdater(PaintLayer* rootLayer)
     : m_geometryMap(UseTransforms)
     , m_rootLayer(rootLayer)
 {
 }
 
 CompositingInputsUpdater::~CompositingInputsUpdater()
 {
 }
 
 void CompositingInputsUpdater::update()
 {
     TRACE_EVENT0("blink", "CompositingInputsUpdater::update");
-    updateRecursive(m_rootLayer, DoNotForceUpdate, AncestorInfo());
+    updateRecursive(m_rootLayer, DoNotForceUpdate, AncestorInfo(m_rootLayer));
 }
 
 static const PaintLayer* findParentLayerOnClippingContainerChain(const PaintLayer* layer)
 {
     LayoutObject* current = layer->layoutObject();
     while (current) {
         if (current->style()->position() == FixedPosition) {
             for (current = current->parent(); current && !current->canContainFixedPositionObjects(); current = current->parent()) {
                 // All types of clips apply to fixed-position descendants of other fixed-position elements.
                 // Note: it's unclear whether this is what the spec says. Firefox does not clip, but Chrome does.
@@ skipping 67 matching lines @@
         if (info.enclosingCompositedLayer)
             info.enclosingCompositedLayer->compositedLayerMapping()->setNeedsGraphicsLayerUpdate(GraphicsLayerUpdateSubtree);
         updateType = ForceUpdate;
     }
 
     if (updateType == ForceUpdate) {
         PaintLayer::AncestorDependentCompositingInputs properties;
         PaintLayer::RareAncestorDependentCompositingInputs rareProperties;
 
         if (!layer->isRootLayer()) {
             properties.clippedAbsoluteBoundingBox = enclosingIntRect(m_geometryMap.absoluteRect(FloatRect(layer->boundingBoxForCompositingOverlapTest())));

[flackr, 2016/02/25 22:10:26]

There seems to be a bit of a problem here. Seems we need the bounding box for
the AncestorDependentCompositingInputs here, but in
LayoutBoxModelObject::offsetForStickyPosition it will use the old
ancestorOverflowLayer. I could separately set the ancestorOverflowLayer and
sticky constraints before this.

[chrishtr, 2016/03/04 20:05:41]

Are you blocked on this? Or did your proposed approach work?

             // FIXME: Setting the absBounds to 1x1 instead of 0x0 makes very little sense,
             // but removing this code will make JSGameBench sad.
             // See https://codereview.chromium.org/13912020/
             if (properties.clippedAbsoluteBoundingBox.isEmpty())
                 properties.clippedAbsoluteBoundingBox.setSize(IntSize(1, 1));
 
             IntRect clipRect = pixelSnappedIntRect(layer->clipper().backgroundClipRect(ClipRectsContext(m_rootLayer, AbsoluteClipRects)).rect());
             properties.clippedAbsoluteBoundingBox.intersect(clipRect);
 
             const PaintLayer* parent = layer->parent();
             rareProperties.opacityAncestor = parent->isTransparent() ? parent : parent->opacityAncestor();
             rareProperties.transformAncestor = parent->hasTransformRelatedProperty() ? parent : parent->transformAncestor();
             rareProperties.filterAncestor = parent->hasFilter() ? parent : parent->filterAncestor();
             bool layerIsFixedPosition = layer->layoutObject()->style()->position() == FixedPosition;
             rareProperties.nearestFixedPositionLayer = layerIsFixedPosition ? layer : parent->nearestFixedPositionLayer();
 
             if (info.hasAncestorWithClipRelatedProperty) {
                 const PaintLayer* parentLayerOnClippingContainerChain = findParentLayerOnClippingContainerChain(layer);
                 const bool parentHasClipRelatedProperty = parentLayerOnClippingContainerChain->layoutObject()->hasClipRelatedProperty();
                 properties.clippingContainer = parentHasClipRelatedProperty ? parentLayerOnClippingContainerChain->layoutObject() : parentLayerOnClippingContainerChain->clippingContainer();
             }
 
+            const LayoutObject* containingBlock = layer->layoutObject()->containingBlock();
+            const PaintLayer* parentLayerOnContainingBlockChain = findParentLayerOnContainingBlockChain(containingBlock);
+
+            rareProperties.ancestorOverflowLayer = parentLayerOnContainingBlockChain->ancestorOverflowLayer();
+            if (parentLayerOnContainingBlockChain->layoutObject()->hasOverflowClip())
+                rareProperties.ancestorOverflowLayer = parentLayerOnContainingBlockChain;
+
             if (info.lastScrollingAncestor) {
-                const LayoutObject* containingBlock = layer->layoutObject()->containingBlock();
-                const PaintLayer* parentLayerOnContainingBlockChain = findParentLayerOnContainingBlockChain(containingBlock);
 
                 rareProperties.ancestorScrollingLayer = parentLayerOnContainingBlockChain->ancestorScrollingLayer();
                 if (parentLayerOnContainingBlockChain->scrollsOverflow())
                     rareProperties.ancestorScrollingLayer = parentLayerOnContainingBlockChain;
 
                 if (layer->layoutObject()->isOutOfFlowPositioned() && !layer->subtreeIsInvisible()) {
                     const PaintLayer* clippingLayer = properties.clippingContainer ? properties.clippingContainer->enclosingLayer() : layer->compositor()->rootLayer();
                     if (hasClippedStackingAncestor(layer, clippingLayer))
                         rareProperties.clipParent = clippingLayer;
                 }
 
                 if (layer->stackingNode()->isTreatedAsOrStackingContext()
                     && rareProperties.ancestorScrollingLayer
                     && !info.ancestorStackingContext->layoutObject()->isDescendantOf(rareProperties.ancestorScrollingLayer->layoutObject()))
                     rareProperties.scrollParent = rareProperties.ancestorScrollingLayer;
             }
+
+            if (layer->layoutObject()->style()->position() == StickyPosition) {
+                if (info.lastOverflowLayer->isRootLayer())
+                    layer->layoutObject()->view()->frameView()->addViewportConstrainedObject(layer->layoutObject());
+                else
+                    layer->layoutObject()->view()->frameView()->removeViewportConstrainedObject(layer->layoutObject());
+                layer->layoutObject()->updateStickyPositionConstraints(info.lastOverflowLayer);
+            }
+        } else {
+            rareProperties.ancestorOverflowLayer = info.lastOverflowLayer;
         }
 
         layer->updateAncestorDependentCompositingInputs(properties, rareProperties, info.hasAncestorWithClipPath);
     }
 
     if (layer->stackingNode()->isStackingContext())
         info.ancestorStackingContext = layer;
 
+    if (layer->layoutObject()->hasOverflowClip())
+        info.lastOverflowLayer = layer;
+
     if (layer->scrollsOverflow())
         info.lastScrollingAncestor = layer;
 
     if (layer->layoutObject()->hasClipRelatedProperty())
         info.hasAncestorWithClipRelatedProperty = true;
 
     if (layer->layoutObject()->hasClipPath())
         info.hasAncestorWithClipPath = true;
 
     bool hasDescendantWithClipPath = false;
@@ skipping 18 matching lines @@
     ASSERT(!layer->childNeedsCompositingInputsUpdate());
     ASSERT(!layer->needsCompositingInputsUpdate());
 
     for (PaintLayer* child = layer->firstChild(); child; child = child->nextSibling())
         assertNeedsCompositingInputsUpdateBitsCleared(child);
 }
 
 #endif
 
 } // namespace blink