[SPv2] Adds pre-computed paint property context to PaintLayer.

third_party/WebKit/Source/core/paint/ObjectPaintProperties.h

 // Copyright 2015 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.
 
 #ifndef ObjectPaintProperties_h
 #define ObjectPaintProperties_h
 
+#include "platform/geometry/LayoutPoint.h"
 #include "platform/graphics/paint/ClipPaintPropertyNode.h"
 #include "platform/graphics/paint/EffectPaintPropertyNode.h"
+#include "platform/graphics/paint/PaintChunkProperties.h"
 #include "platform/graphics/paint/TransformPaintPropertyNode.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
-// The minimal set of paint properties created by a |LayoutObject|. These
-// properties encode a hierachy of transforms, clips, effects, etc, both between
-// LayoutObjects (each property has a parent) and among the properties of a
-// single LayoutObject (e.g., transform and perspective with the correct parent
-// relationship to represent ordering).
-//
-// This differs from |PaintChunkProperties| because it can store multiple
-// properties of the same type (e.g., transform and perspective which are both
-// transforms).
+// This class stores property tree related information associated with a LayoutObject.
+// Currently there are two groups of information:
+// 1. The set of property nodes created locally by this LayoutObject.
+// 2. [Optional] A suite of property nodes (PaintChunkProperties) and paint offset
+//    that can be used to paint the border box of this LayoutObject.
 class ObjectPaintProperties {
     WTF_MAKE_NONCOPYABLE(ObjectPaintProperties);
     USING_FAST_MALLOC(ObjectPaintProperties);
 public:
+    struct LocalBorderBoxProperties;
+
     static PassOwnPtr<ObjectPaintProperties> create(
         PassRefPtr<TransformPaintPropertyNode> paintOffsetTranslation,
         PassRefPtr<TransformPaintPropertyNode> transform,
         PassRefPtr<EffectPaintPropertyNode> effect,
         PassRefPtr<ClipPaintPropertyNode> overflowClip,
         PassRefPtr<TransformPaintPropertyNode> perspective,
-        PassRefPtr<TransformPaintPropertyNode> scrollTranslation)
+        PassRefPtr<TransformPaintPropertyNode> scrollTranslation,
+        PassOwnPtr<LocalBorderBoxProperties> localBorderBoxProperties)
     {
-        return adoptPtr(new ObjectPaintProperties(paintOffsetTranslation, transform, effect, overflowClip, perspective, scrollTranslation));
+        return adoptPtr(new ObjectPaintProperties(paintOffsetTranslation, transform, effect, overflowClip, perspective, scrollTranslation, localBorderBoxProperties));
     }
 
     // The hierarchy of transform subtree created by a LayoutObject.
     // [ paintOffsetTranslation ]           Normally paint offset is accumulated without creating a node
     // |                                    until we see, for example, transform or position:fixed.
     // +---[ transform ]                    The space created by CSS transform.
+    //     |                                This is the local border box space, see: LocalBorderBoxProperties below.
     //     +---[ perspective ]              The space created by CSS perspective.
     //         +---[ scrollTranslation ]    The space created by overflow clip.
     TransformPaintPropertyNode* paintOffsetTranslation() const { return m_paintOffsetTranslation.get(); }
     TransformPaintPropertyNode* transform() const { return m_transform.get(); }
     TransformPaintPropertyNode* perspective() const { return m_perspective.get(); }
     TransformPaintPropertyNode* scrollTranslation() const { return m_scrollTranslation.get(); }
 
     // Transform that applies to layer contents, or nullptr if this object
     // doesn't define one.
     TransformPaintPropertyNode* transformForLayerContents() const;
 
     EffectPaintPropertyNode* effect() const { return m_effect.get(); }
 
     ClipPaintPropertyNode* overflowClip() const { return m_overflowClip.get(); }
 
+    // This is a complete set of property nodes that should be used as a starting point to paint
+    // this layout object. It is needed becauase some property inherits from the containing block,
+    // not painting parent, thus can't be derived in O(1) during paint walk.
+    // Note: If this layout object has transform or stacking-context effects, those are already
+    // baked into in the context here. However for properties that affects only children,
+    // for example, perspective and overflow clip, those should be applied by the painter
+    // at the right painting step.
+    struct LocalBorderBoxProperties {
+        LayoutPoint paintOffset;
+        PaintChunkProperties properties;
+    };
+    LocalBorderBoxProperties* localBorderBoxProperties() const { return m_localBorderBoxProperties.get(); }
+
 private:
     ObjectPaintProperties(
         PassRefPtr<TransformPaintPropertyNode> paintOffsetTranslation,
         PassRefPtr<TransformPaintPropertyNode> transform,
         PassRefPtr<EffectPaintPropertyNode> effect,
         PassRefPtr<ClipPaintPropertyNode> overflowClip,
         PassRefPtr<TransformPaintPropertyNode> perspective,
-        PassRefPtr<TransformPaintPropertyNode> scrollTranslation)
+        PassRefPtr<TransformPaintPropertyNode> scrollTranslation,
+        PassOwnPtr<LocalBorderBoxProperties> localBorderBoxProperties)
         : m_paintOffsetTranslation(paintOffsetTranslation)
         , m_transform(transform)
         , m_effect(effect)
         , m_overflowClip(overflowClip)
         , m_perspective(perspective)
-        , m_scrollTranslation(scrollTranslation) { }
+        , m_scrollTranslation(scrollTranslation)
+        , m_localBorderBoxProperties(localBorderBoxProperties) { }
 
     RefPtr<TransformPaintPropertyNode> m_paintOffsetTranslation;
     RefPtr<TransformPaintPropertyNode> m_transform;
     RefPtr<EffectPaintPropertyNode> m_effect;
     RefPtr<ClipPaintPropertyNode> m_overflowClip;
     RefPtr<TransformPaintPropertyNode> m_perspective;
     RefPtr<TransformPaintPropertyNode> m_scrollTranslation;
+
+    OwnPtr<LocalBorderBoxProperties> m_localBorderBoxProperties;
 };
 
 } // namespace blink
 
 #endif // ObjectPaintProperties_h