[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).
 class ObjectPaintProperties {
     WTF_MAKE_NONCOPYABLE(ObjectPaintProperties);
     USING_FAST_MALLOC(ObjectPaintProperties);
 public:
+    struct PropertyTreeContext;
+
     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<PropertyTreeContext> propertyTreeContext)
     {
-        return adoptPtr(new ObjectPaintProperties(paintOffsetTranslation, transform, effect, overflowClip, perspective, scrollTranslation));
+        return adoptPtr(new ObjectPaintProperties(paintOffsetTranslation, transform, effect, overflowClip, perspective, scrollTranslation, propertyTreeContext));
     }
 
     // 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.

[pdr., 2016/02/03 23:56:11]

WDYT about updating this diagram to include the context?

[trchen, 2016/02/04 00:03:02]

Acknowledged.

     //     +---[ 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;

[pdr., 2016/02/03 23:56:11]

Does transformForLayerContents need to be updated to return the
propertyTreeContext node?

[trchen, 2016/02/04 00:03:02]

Ah ha! Yes we can make use of the cache to get rid of the cascading ifs. Though
I'll have to look through the call sites to make sure. Perhaps in another
cleanup CL?

[trchen, 2016/02/04 00:07:51]

NVM. We can simply remove it with my CL #2.

 
     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 PropertyTreeContext {
+        LayoutPoint paintOffset;
+        PaintChunkProperties properties;
+    };
+    PropertyTreeContext* propertyTreeContext() const { return m_propertyTreeContext.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<PropertyTreeContext> propertyTreeContext)
         : m_paintOffsetTranslation(paintOffsetTranslation)
         , m_transform(transform)
         , m_effect(effect)
         , m_overflowClip(overflowClip)
         , m_perspective(perspective)
-        , m_scrollTranslation(scrollTranslation) { }
+        , m_scrollTranslation(scrollTranslation)
+        , m_propertyTreeContext(propertyTreeContext) { }
 
     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<PropertyTreeContext> m_propertyTreeContext;
 };
 
 } // namespace blink
 
 #endif // ObjectPaintProperties_h