Separate the geometry update from rebuilding the GraphicsLayer tree

Source/core/rendering/compositing/CompositingRequirementsUpdater.h

+/*
+ * 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.
+ */
+
+#ifndef CompositingRequirementsUpdater_h
+#define CompositingRequirementsUpdater_h
+
+#include "platform/geometry/IntRect.h"
+#include "platform/graphics/CompositingReasons.h"
+#include "wtf/Vector.h"
+
+namespace WebCore {
+
+class CompositingReasonFinder;
+class RenderLayer;
+class RenderObject;
+class RenderPart;
+class RenderView;
+
+class CompositingRequirementsUpdater {
+public:
+    CompositingRequirementsUpdater(RenderView&, CompositingReasonFinder&, bool* needsToRecomputeCompositingRequirements);
+    ~CompositingRequirementsUpdater();
+
+    //  Recurse through the layers in z-index and overflow order (which is equivalent to painting order)
+    //  For the z-order children of a compositing layer:
+    //      If a child layers has a compositing layer, then all subsequent layers must
+    //      be compositing in order to render above that layer.
+    //
+    //      If a child in the negative z-order list is compositing, then the layer itself
+    //      must be compositing so that its contents render over that child.
+    //      This implies that its positive z-index children must also be compositing.
+    //
+    void update(RenderLayer* root);
+
+private:
+    class OverlapMap;
+    class RecursionData;
+
+    void updateRecursive(RenderLayer* ancestorLayer, RenderLayer* currentLayer, OverlapMap&, RecursionData&, bool& descendantHas3DTransform, Vector<RenderLayer*>& unclippedDescendants, IntRect& absoluteDecendantBoundingBox);
+    bool isRunningAcceleratedTransformAnimation(RenderObject*) const;
+
+    RenderView& m_renderView;
+    CompositingReasonFinder& m_compositingReasonFinder;
+
+    // FIXME: CompositingRequirementsUpdater should not effect this state.
+    bool* m_needsToRecomputeCompositingRequirements;
+};
+
+} // namespace WebCore
+
+#endif // CompositingRequirementsUpdater_h