Remove most of the old compositing code.

sky/engine/core/rendering/compositing/CompositingRequirementsUpdater.cpp

Index: sky/engine/core/rendering/compositing/CompositingRequirementsUpdater.cpp
diff --git a/sky/engine/core/rendering/compositing/CompositingRequirementsUpdater.cpp b/sky/engine/core/rendering/compositing/CompositingRequirementsUpdater.cpp
deleted file mode 100644
index 3ca42ef8372589b359afca77950050450f87cffd..0000000000000000000000000000000000000000
--- a/sky/engine/core/rendering/compositing/CompositingRequirementsUpdater.cpp
+++ /dev/null
@@ -1,390 +0,0 @@
-/*
- * Copyright (C) 2009, 2010 Apple Inc. All rights reserved.
- * Copyright (C) 2014 Google 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
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
- * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
- * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include "sky/engine/config.h"
-#include "sky/engine/core/rendering/compositing/CompositingRequirementsUpdater.h"
-
-#include "sky/engine/core/rendering/RenderLayerStackingNode.h"
-#include "sky/engine/core/rendering/RenderLayerStackingNodeIterator.h"
-#include "sky/engine/core/rendering/RenderView.h"
-#include "sky/engine/core/rendering/compositing/RenderLayerCompositor.h"
-#include "sky/engine/platform/TraceEvent.h"
-
-namespace blink {
-
-class OverlapMapContainer {
-public:
-    void add(const IntRect& bounds)
-    {
-        m_layerRects.append(bounds);
-        m_boundingBox.unite(bounds);
-    }
-
-    bool overlapsLayers(const IntRect& bounds) const
-    {
-        // Checking with the bounding box will quickly reject cases when
-        // layers are created for lists of items going in one direction and
-        // never overlap with each other.
-        if (!bounds.intersects(m_boundingBox))
-            return false;
-        for (unsigned i = 0; i < m_layerRects.size(); i++) {
-            if (m_layerRects[i].intersects(bounds))
-                return true;
-        }
-        return false;
-    }
-
-    void unite(const OverlapMapContainer& otherContainer)
-    {
-        m_layerRects.appendVector(otherContainer.m_layerRects);
-        m_boundingBox.unite(otherContainer.m_boundingBox);
-    }
-private:
-    Vector<IntRect, 64> m_layerRects;
-    IntRect m_boundingBox;
-};
-
-class CompositingRequirementsUpdater::OverlapMap {
-    WTF_MAKE_NONCOPYABLE(OverlapMap);
-public:
-    OverlapMap()
-    {
-        // Begin by assuming the root layer will be composited so that there
-        // is something on the stack. The root layer should also never get a
-        // finishCurrentOverlapTestingContext() call.
-        beginNewOverlapTestingContext();
-    }
-
-    void add(RenderLayer* layer, const IntRect& bounds)
-    {
-        ASSERT(!layer->isRootLayer());
-        if (bounds.isEmpty())
-            return;
-
-        // Layers do not contribute to overlap immediately--instead, they will
-        // contribute to overlap as soon as they have been recursively processed
-        // and popped off the stack.
-        ASSERT(m_overlapStack.size() >= 2);
-        m_overlapStack[m_overlapStack.size() - 2].add(bounds);
-    }
-
-    bool overlapsLayers(const IntRect& bounds) const
-    {
-        return m_overlapStack.last().overlapsLayers(bounds);
-    }
-
-    void beginNewOverlapTestingContext()
-    {
-        // This effectively creates a new "clean slate" for overlap state.
-        // This is used when we know that a subtree or remaining set of
-        // siblings does not need to check overlap with things behind it.
-        m_overlapStack.append(OverlapMapContainer());
-    }
-
-    void finishCurrentOverlapTestingContext()
-    {
-        // The overlap information on the top of the stack is still necessary
-        // for checking overlap of any layers outside this context that may
-        // overlap things from inside this context. Therefore, we must merge
-        // the information from the top of the stack before popping the stack.
-        //
-        // FIXME: we may be able to avoid this deep copy by rearranging how
-        //        overlapMap state is managed.
-        m_overlapStack[m_overlapStack.size() - 2].unite(m_overlapStack.last());
-        m_overlapStack.removeLast();
-    }
-
-private:
-    Vector<OverlapMapContainer> m_overlapStack;
-};
-
-class CompositingRequirementsUpdater::RecursionData {
-public:
-    explicit RecursionData(RenderLayer* compositingAncestor)
-        : m_compositingAncestor(compositingAncestor)
-        , m_subtreeIsCompositing(false)
-        , m_testingOverlap(true)
-    {
-    }
-
-    RenderLayer* m_compositingAncestor;
-    bool m_subtreeIsCompositing;
-    bool m_testingOverlap;
-};
-
-static bool requiresCompositingOrSquashing(CompositingReasons reasons)
-{
-#if ENABLE(ASSERT)
-    bool fastAnswer = reasons != CompositingReasonNone;
-    bool slowAnswer = requiresCompositing(reasons) || requiresSquashing(reasons);
-    ASSERT(fastAnswer == slowAnswer);
-#endif
-    return reasons != CompositingReasonNone;
-}
-
-static CompositingReasons subtreeReasonsForCompositing(RenderLayer* layer, bool hasCompositedDescendants, bool has3DTransformedDescendants)
-{
-    CompositingReasons subtreeReasons = CompositingReasonNone;
-
-    // When a layer has composited descendants, some effects, like 2d transforms, filters, masks etc must be implemented
-    // via compositing so that they also apply to those composited descdendants.
-    if (hasCompositedDescendants) {
-        subtreeReasons |= layer->potentialCompositingReasonsFromStyle() & CompositingReasonComboCompositedDescendants;
-
-
-        // FIXME: This should move into CompositingReasonFinder::potentialCompositingReasonsFromStyle, but
-        // theres a poor interaction with RenderTextControlSingleLine, which sets this hasOverflowClip directly.
-        if (layer->renderer()->hasClipOrOverflowClip())
-            subtreeReasons |= CompositingReasonClipsCompositingDescendants;
-    }
-
-    // A layer with preserve-3d or perspective only needs to be composited if there are descendant layers that
-    // will be affected by the preserve-3d or perspective.
-    if (has3DTransformedDescendants)
-        subtreeReasons |= layer->potentialCompositingReasonsFromStyle() & CompositingReasonCombo3DDescendants;
-
-    return subtreeReasons;
-}
-
-CompositingRequirementsUpdater::CompositingRequirementsUpdater(RenderView& renderView, CompositingReasonFinder& compositingReasonFinder)
-    : m_renderView(renderView)
-    , m_compositingReasonFinder(compositingReasonFinder)
-{
-}
-
-CompositingRequirementsUpdater::~CompositingRequirementsUpdater()
-{
-}
-
-void CompositingRequirementsUpdater::update(RenderLayer* root)
-{
-    TRACE_EVENT0("blink", "CompositingRequirementsUpdater::updateRecursive");
-
-    // Go through the layers in presentation order, so that we can compute which RenderLayers need compositing layers.
-    // FIXME: we could maybe do this and the hierarchy udpate in one pass, but the parenting logic would be more complex.
-    RecursionData recursionData(root);
-    OverlapMap overlapTestRequestMap;
-    bool saw3DTransform = false;
-
-    // FIXME: Passing these unclippedDescendants down and keeping track
-    // of them dynamically, we are requiring a full tree walk. This
-    // should be removed as soon as proper overlap testing based on
-    // scrolling and animation bounds is implemented (crbug.com/252472).
-    Vector<RenderLayer*> unclippedDescendants;
-    IntRect absoluteDecendantBoundingBox;
-    updateRecursive(0, root, overlapTestRequestMap, recursionData, saw3DTransform, unclippedDescendants, absoluteDecendantBoundingBox);
-}
-
-void CompositingRequirementsUpdater::updateRecursive(RenderLayer* ancestorLayer, RenderLayer* layer, OverlapMap& overlapMap, RecursionData& currentRecursionData, bool& descendantHas3DTransform, Vector<RenderLayer*>& unclippedDescendants, IntRect& absoluteDecendantBoundingBox)
-{
-    RenderLayerCompositor* compositor = m_renderView.compositor();
-
-    layer->stackingNode()->updateLayerListsIfNeeded();
-
-    CompositingReasons reasonsToComposite = CompositingReasonNone;
-    CompositingReasons directReasons = m_compositingReasonFinder.directReasons(layer);
-
-    if (compositor->canBeComposited(layer))
-        reasonsToComposite |= directReasons;
-
-    // Next, accumulate reasons related to overlap.
-    // If overlap testing is used, this reason will be overridden. If overlap testing is not
-    // used, we must assume we overlap if there is anything composited behind us in paint-order.
-    CompositingReasons overlapCompositingReason = currentRecursionData.m_subtreeIsCompositing ? CompositingReasonAssumedOverlap : CompositingReasonNone;
-
-    if (m_renderView.compositor()->preferCompositingToLCDTextEnabled()) {
-        Vector<size_t> unclippedDescendantsToRemove;
-        for (size_t i = 0; i < unclippedDescendants.size(); i++) {
-            RenderLayer* unclippedDescendant = unclippedDescendants.at(i);
-            // If we've reached the containing block of one of the unclipped
-            // descendants, that element is no longer relevant to whether or not we
-            // should opt in. Unfortunately we can't easily remove from the list
-            // while we're iterating, so we have to store it for later removal.
-            if (unclippedDescendant->renderer()->containingBlock() == layer->renderer()) {
-                unclippedDescendantsToRemove.append(i);
-                continue;
-            }
-            if (layer->scrollsWithRespectTo(unclippedDescendant))
-                reasonsToComposite |= CompositingReasonAssumedOverlap;
-        }
-
-        // Remove irrelevant unclipped descendants in reverse order so our stored
-        // indices remain valid.
-        for (size_t i = 0; i < unclippedDescendantsToRemove.size(); i++)
-            unclippedDescendants.remove(unclippedDescendantsToRemove.at(unclippedDescendantsToRemove.size() - i - 1));
-
-        if (reasonsToComposite & CompositingReasonOutOfFlowClipping)
-            unclippedDescendants.append(layer);
-    }
-
-    const IntRect& absBounds = layer->clippedAbsoluteBoundingBox();
-    absoluteDecendantBoundingBox = absBounds;
-
-    if (currentRecursionData.m_testingOverlap && !requiresCompositingOrSquashing(directReasons))
-        overlapCompositingReason = overlapMap.overlapsLayers(absBounds) ? CompositingReasonOverlap : CompositingReasonNone;
-
-    reasonsToComposite |= overlapCompositingReason;
-
-    // The children of this layer don't need to composite, unless there is
-    // a compositing layer among them, so start by inheriting the compositing
-    // ancestor with m_subtreeIsCompositing set to false.
-    RecursionData childRecursionData = currentRecursionData;
-    childRecursionData.m_subtreeIsCompositing = false;
-
-    bool willBeCompositedOrSquashed = compositor->canBeComposited(layer) && requiresCompositingOrSquashing(reasonsToComposite);
-    if (willBeCompositedOrSquashed) {
-        // Tell the parent it has compositing descendants.
-        currentRecursionData.m_subtreeIsCompositing = true;
-        // This layer now acts as the ancestor for kids.
-        childRecursionData.m_compositingAncestor = layer;
-
-        // Here we know that all children and the layer's own contents can blindly paint into
-        // this layer's backing, until a descendant is composited. So, we don't need to check
-        // for overlap with anything behind this layer.
-        overlapMap.beginNewOverlapTestingContext();
-        // This layer is going to be composited, so children can safely ignore the fact that there's an
-        // animation running behind this layer, meaning they can rely on the overlap map testing again.
-        childRecursionData.m_testingOverlap = true;
-    }
-
-#if ENABLE(ASSERT)
-    LayerListMutationDetector mutationChecker(layer->stackingNode());
-#endif
-
-    bool anyDescendantHas3DTransform = false;
-    bool willHaveForegroundLayer = false;
-
-    if (layer->stackingNode()->isStackingContext()) {
-        RenderLayerStackingNodeIterator iterator(*layer->stackingNode(), NegativeZOrderChildren);
-        while (RenderLayerStackingNode* curNode = iterator.next()) {
-            IntRect absoluteChildDecendantBoundingBox;
-            updateRecursive(layer, curNode->layer(), overlapMap, childRecursionData, anyDescendantHas3DTransform, unclippedDescendants, absoluteChildDecendantBoundingBox);
-            absoluteDecendantBoundingBox.unite(absoluteChildDecendantBoundingBox);
-
-            // If we have to make a layer for this child, make one now so we can have a contents layer
-            // (since we need to ensure that the -ve z-order child renders underneath our contents).
-            if (childRecursionData.m_subtreeIsCompositing) {
-                reasonsToComposite |= CompositingReasonNegativeZIndexChildren;
-
-                if (!willBeCompositedOrSquashed) {
-                    // make layer compositing
-                    childRecursionData.m_compositingAncestor = layer;
-                    overlapMap.beginNewOverlapTestingContext();
-                    willBeCompositedOrSquashed = true;
-                    willHaveForegroundLayer = true;
-
-                    // FIXME: temporary solution for the first negative z-index composited child:
-                    //        re-compute the absBounds for the child so that we can add the
-                    //        negative z-index child's bounds to the new overlap context.
-                    overlapMap.beginNewOverlapTestingContext();
-                    overlapMap.add(curNode->layer(), curNode->layer()->clippedAbsoluteBoundingBox());
-                    overlapMap.finishCurrentOverlapTestingContext();
-                }
-            }
-        }
-    }
-
-    if (willHaveForegroundLayer) {
-        ASSERT(willBeCompositedOrSquashed);
-        // A foreground layer effectively is a new backing for all subsequent children, so
-        // we don't need to test for overlap with anything behind this. So, we can finish
-        // the previous context that was accumulating rects for the negative z-index
-        // children, and start with a fresh new empty context.
-        overlapMap.finishCurrentOverlapTestingContext();
-        overlapMap.beginNewOverlapTestingContext();
-        // This layer is going to be composited, so children can safely ignore the fact that there's an
-        // animation running behind this layer, meaning they can rely on the overlap map testing again
-        childRecursionData.m_testingOverlap = true;
-    }
-
-    RenderLayerStackingNodeIterator iterator(*layer->stackingNode(), NormalFlowChildren | PositiveZOrderChildren);
-    while (RenderLayerStackingNode* curNode = iterator.next()) {
-        IntRect absoluteChildDecendantBoundingBox;
-        updateRecursive(layer, curNode->layer(), overlapMap, childRecursionData, anyDescendantHas3DTransform, unclippedDescendants, absoluteChildDecendantBoundingBox);
-        absoluteDecendantBoundingBox.unite(absoluteChildDecendantBoundingBox);
-    }
-
-    // Now that the subtree has been traversed, we can check for compositing reasons that depended on the state of the subtree.
-
-    // Subsequent layers in the parent's stacking context may also need to composite.
-    if (childRecursionData.m_subtreeIsCompositing)
-        currentRecursionData.m_subtreeIsCompositing = true;
-
-    // Set the flag to say that this SC has compositing children.
-    layer->setHasCompositingDescendant(childRecursionData.m_subtreeIsCompositing);
-
-    if (layer->isRootLayer()) {
-        // The root layer needs to be composited if anything else in the tree is composited.
-        // Otherwise, we can disable compositing entirely.
-        if (childRecursionData.m_subtreeIsCompositing || requiresCompositingOrSquashing(reasonsToComposite) || compositor->rootShouldAlwaysComposite()) {
-            reasonsToComposite |= CompositingReasonRoot;
-        } else {
-            compositor->setCompositingModeEnabled(false);
-            reasonsToComposite = CompositingReasonNone;
-        }
-    } else {
-        // All layers (even ones that aren't being composited) need to get added to
-        // the overlap map. Layers that are not separately composited will paint into their
-        // compositing ancestor's backing, and so are still considered for overlap.
-        if (childRecursionData.m_compositingAncestor && !childRecursionData.m_compositingAncestor->isRootLayer())
-            overlapMap.add(layer, absBounds);
-
-        // Now check for reasons to become composited that depend on the state of descendant layers.
-        CompositingReasons subtreeCompositingReasons = subtreeReasonsForCompositing(layer, childRecursionData.m_subtreeIsCompositing, anyDescendantHas3DTransform);
-        reasonsToComposite |= subtreeCompositingReasons;
-        if (!willBeCompositedOrSquashed && compositor->canBeComposited(layer) && requiresCompositingOrSquashing(subtreeCompositingReasons)) {
-            childRecursionData.m_compositingAncestor = layer;
-            // FIXME: this context push is effectively a no-op but needs to exist for
-            // now, because the code is designed to push overlap information to the
-            // second-from-top context of the stack.
-            overlapMap.beginNewOverlapTestingContext();
-            overlapMap.add(layer, absoluteDecendantBoundingBox);
-            willBeCompositedOrSquashed = true;
-        }
-
-        if (willBeCompositedOrSquashed)
-            reasonsToComposite |= layer->potentialCompositingReasonsFromStyle() & CompositingReasonInlineTransform;
-
-        // Turn overlap testing off for later layers if it's already off, or if we have an animating transform.
-        // Note that if the layer clips its descendants, there's no reason to propagate the child animation to the parent layers. That's because
-        // we know for sure the animation is contained inside the clipping rectangle, which is already added to the overlap map.
-        bool isCompositedClippingLayer = compositor->canBeComposited(layer) && (reasonsToComposite & CompositingReasonClipsCompositingDescendants);
-        bool isCompositedWithInlineTransform = reasonsToComposite & CompositingReasonInlineTransform;
-        if ((!childRecursionData.m_testingOverlap && !isCompositedClippingLayer) || layer->renderer()->style()->hasCurrentTransformAnimation() || isCompositedWithInlineTransform)
-            currentRecursionData.m_testingOverlap = false;
-
-        if (childRecursionData.m_compositingAncestor == layer)
-            overlapMap.finishCurrentOverlapTestingContext();
-
-        descendantHas3DTransform |= anyDescendantHas3DTransform || layer->has3DTransform();
-    }
-
-    // At this point we have finished collecting all reasons to composite this layer.
-    layer->setCompositingReasons(reasonsToComposite);
-
-}
-
-} // namespace blink