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

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

Index: third_party/WebKit/Source/core/paint/ObjectPaintProperties.h
diff --git a/third_party/WebKit/Source/core/paint/ObjectPaintProperties.h b/third_party/WebKit/Source/core/paint/ObjectPaintProperties.h
index 6048057f8bf45ca6b03a8d8d4e3967d9cb5f3968..499ce448248d5c7bd6cc02f6c4764d94a1a92225 100644
--- a/third_party/WebKit/Source/core/paint/ObjectPaintProperties.h
+++ b/third_party/WebKit/Source/core/paint/ObjectPaintProperties.h
@@ -5,8 +5,10 @@
 #ifndef ObjectPaintProperties_h
 #define ObjectPaintProperties_h
 
+#include "platform/geometry/LayoutPoint.h"

[pdr., 2016/02/04 04:54:01]

Can you update PaintPropertyTreePrinter too?

To test, I usually add this to FrameView.cpp:
#include "core/paint/PaintPropertyTreePrinter.h"
and
showTransformPropertyTree(*this);
showClipPropertyTree(*this);
to the end of FrameView::updatePaintProperties.

Or, if you don't find this class useful, lets delete PaintPropertyTreePrinter in
a followup. AFAIK, I'm the only user.

[trchen, 2016/02/04 23:08:40]

Acknowledged.

[trchen, 2016/02/04 23:49:01]

I examined PaintPropertyTreePainter. The painter only dumps the property tree
hierarchy, but this CL doesn't change the tree hierarchy at all. For the newly
added information you probably want to show them in the layout tree dumper.

 #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"
@@ -27,21 +29,26 @@ 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.
+    //     |                                It is the local border box space the painter expects,

[pdr., 2016/02/04 04:54:01]

This helped me understand the situation. Maybe even rephrase this a little:
"<-- This is the local border box space, see: PropertyTreeContext below."

[trchen, 2016/02/04 23:08:40]

Acknowledged.

+    //     |                                see PropertyTreeContext below.
     //     +---[ perspective ]              The space created by CSS perspective.
     //         +---[ scrollTranslation ]    The space created by overflow clip.
     TransformPaintPropertyNode* paintOffsetTranslation() const { return m_paintOffsetTranslation.get(); }
@@ -57,6 +64,19 @@ public:
 
     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 {

[pdr., 2016/02/04 04:54:01]

WDYT of "LocalBorderBoxProperties"? In reading through this patch (and your
comment above), I realized this may be a better name since it implies that
transform may come before, and overflow clip after, etc.

[trchen, 2016/02/04 23:08:40]

Sounds clear! Let's do that.

+        LayoutPoint paintOffset;
+        PaintChunkProperties properties;

[pdr., 2016/02/04 04:54:01]

Can you think of a case when the effect/filter property ever be used?

[trchen, 2016/02/04 23:08:40]

Probably not. Effect node can be derived from the paint walk in O(1). It is
there just for convenience.

+    };
+    PropertyTreeContext* propertyTreeContext() const { return m_propertyTreeContext.get(); }
+
 private:
     ObjectPaintProperties(
         PassRefPtr<TransformPaintPropertyNode> paintOffsetTranslation,
@@ -64,13 +84,15 @@ private:
         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;
@@ -78,6 +100,8 @@ private:
     RefPtr<ClipPaintPropertyNode> m_overflowClip;
     RefPtr<TransformPaintPropertyNode> m_perspective;
     RefPtr<TransformPaintPropertyNode> m_scrollTranslation;
+
+    OwnPtr<PropertyTreeContext> m_propertyTreeContext;
 };
 
 } // namespace blink