Adapt and reland old position sticky implementation

Source/core/layout/compositing/CompositedDeprecatedPaintLayerMapping.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 30 matching lines @@
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/layout/LayoutEmbeddedObject.h"
 #include "core/layout/LayoutHTMLCanvas.h"
 #include "core/layout/LayoutImage.h"
 #include "core/layout/LayoutPart.h"
 #include "core/layout/LayoutVideo.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/compositing/DeprecatedPaintLayerCompositor.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/Page.h"
+#include "core/page/scrolling/ScrollingConstraints.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
 #include "core/paint/DeprecatedPaintLayerPainter.h"
 #include "core/paint/DeprecatedPaintLayerStackingNodeIterator.h"
 #include "core/paint/ScrollableAreaPainter.h"
 #include "core/paint/TransformRecorder.h"
 #include "core/plugins/PluginView.h"
 #include "platform/LengthFunctions.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/fonts/FontCache.h"
 #include "platform/geometry/TransformState.h"
 #include "platform/graphics/BitmapImage.h"
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/paint/ClipDisplayItem.h"
 #include "platform/graphics/paint/DisplayItemList.h"
 #include "platform/graphics/paint/TransformDisplayItem.h"
+#include "public/platform/WebLayerPositionConstraint.h"
 #include "wtf/CurrentTime.h"
 #include "wtf/text/StringBuilder.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
 static IntRect clipBox(LayoutBox* layoutObject);
 
 static IntRect contentsRect(const LayoutObject* layoutObject)
@@ skipping 146 matching lines @@
 }
 
 void CompositedDeprecatedPaintLayerMapping::createPrimaryGraphicsLayer()
 {
     m_graphicsLayer = createGraphicsLayer(m_owningLayer.compositingReasons());
 
     updateOpacity(layoutObject()->styleRef());
     updateTransform(layoutObject()->styleRef());
     updateFilters(layoutObject()->styleRef());
     updateBackdropFilters(layoutObject()->styleRef());
+    updateStickyConstraints(layoutObject()->styleRef());
 
     if (RuntimeEnabledFeatures::cssCompositingEnabled()) {
         updateLayerBlendMode(layoutObject()->styleRef());
         updateIsRootForIsolatedGroup();
     }
 }
 
 void CompositedDeprecatedPaintLayerMapping::destroyGraphicsLayers()
 {
     if (m_graphicsLayer)
@@ skipping 39 matching lines @@
 void CompositedDeprecatedPaintLayerMapping::updateBackdropFilters(const ComputedStyle& style)
 {
     m_graphicsLayer->setBackdropFilters(owningLayer().computeBackdropFilterOperations(style));
 }
 
 void CompositedDeprecatedPaintLayerMapping::updateLayerBlendMode(const ComputedStyle& style)
 {
     setBlendMode(style.blendMode());
 }
 
+void CompositedDeprecatedPaintLayerMapping::updateStickyConstraints(const ComputedStyle& style)
+{
+    bool sticky = style.position() == EPosition::StickyPosition;
+    if (sticky) {
+        const DeprecatedPaintLayer* ancestorScrollingLayer = m_owningLayer.ancestorScrollingLayer();
+        if (ancestorScrollingLayer) {
+            sticky = ancestorScrollingLayer->needsCompositedScrolling();
+        } else {
+            // If there's no ancestor scrolling layer the viewport is our ancestor scroller.
+            sticky = layoutObject()->view()->frameView()->isScrollable();
+        }
+    }
+
+    WebLayerStickyPositionConstraint webConstraint;
+    if (sticky) {
+        LayoutBoxModelObject* boxModelObject = m_owningLayer.layoutObject();
+        LayoutRect containingRect = boxModelObject->computeStickyConstrainingRect();
+        StickyPositionViewportConstraints constraints;
+        boxModelObject->computeStickyPositionConstraints(constraints, containingRect);
+
+        webConstraint.isSticky = true;
+
+        webConstraint.isAnchoredLeft = constraints.anchorEdges() & ViewportConstraints::AnchorEdgeLeft;
+        webConstraint.isAnchoredRight = constraints.anchorEdges() & ViewportConstraints::AnchorEdgeRight;
+        webConstraint.isAnchoredTop = constraints.anchorEdges() & ViewportConstraints::AnchorEdgeTop;
+        webConstraint.isAnchoredBottom = constraints.anchorEdges() & ViewportConstraints::AnchorEdgeBottom;
+
+        webConstraint.leftOffset = constraints.leftOffset().toFloat();
+        webConstraint.rightOffset = constraints.rightOffset().toFloat();
+        webConstraint.topOffset = constraints.topOffset().toFloat();
+        webConstraint.bottomOffset = constraints.bottomOffset().toFloat();
+
+        webConstraint.absoluteStickyBoxRect = enclosingIntRect(constraints.absoluteStickyBoxRect());
+        webConstraint.absoluteContainingBlockRect = enclosingIntRect(constraints.absoluteContainingBlockRect());
+    }
+
+    m_graphicsLayer->platformLayer()->setStickyPositionConstraint(webConstraint);
+}
+
 void CompositedDeprecatedPaintLayerMapping::updateIsRootForIsolatedGroup()
 {
     bool isolate = m_owningLayer.shouldIsolateCompositedDescendants();
 
     // non stacking context layers should never isolate
     ASSERT(m_owningLayer.stackingNode()->isStackingContext() || !isolate);
 
     m_graphicsLayer->setIsRootForIsolatedGroup(isolate);
 }
 
@@ skipping 423 matching lines @@
     updateBackgroundColor();
     updateDrawsContent();
     updateContentsOpaque();
     updateAfterPartResize();
     updateRenderingContext();
     updateShouldFlattenTransform();
     updateChildrenTransform();
     updateScrollParent(scrollParent());
     registerScrollingLayers();
 
+    updateStickyConstraints(layoutObject()->styleRef());
+
     updateCompositingReasons();
 }
 
 void CompositedDeprecatedPaintLayerMapping::updateMainGraphicsLayerGeometry(const IntRect& relativeCompositingBounds, const IntRect& localCompositingBounds, const IntPoint& graphicsLayerParentLocation)
 {
     m_graphicsLayer->setPosition(FloatPoint(relativeCompositingBounds.location() - graphicsLayerParentLocation));
     m_graphicsLayer->setOffsetFromLayoutObject(toIntSize(localCompositingBounds.location()));
 
     FloatSize oldSize = m_graphicsLayer->size();
     const IntSize& contentsSize = relativeCompositingBounds.size();
@@ skipping 1653 matching lines @@
     } else if (graphicsLayer == m_scrollingBlockSelectionLayer.get()) {
         name = "Scrolling Block Selection Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink