Preliminary paint property walk implementation for SPv2

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

Index: third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h
diff --git a/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h b/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h
new file mode 100644
index 0000000000000000000000000000000000000000..2e99af6005622495547588620e14f75f6b3809bf
--- /dev/null
+++ b/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h
@@ -0,0 +1,30 @@
+// 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 PaintPropertyTreeBuilder_h
+#define PaintPropertyTreeBuilder_h
+
+namespace blink {
+
+class FrameView;
+class LayoutBoxModelObject;
+class LayoutObject;
+struct PaintPropertyTreeNode;
+
+class PaintPropertyTreeBuilder {

[jbroman, 2015/10/14 15:11:58]

Will this object have state in the future? If not, this could just be a function
and the rest of these function declarations wouldn't need to be exposed in the
header.

[trchen, 2015/10/14 22:51:13]

I think it is likely we will add some state. Let's say if later we decide to go
back to vector to allocate property nodes. Also it may be handy to save some
global state, like Setting*, root local frame, or resource accounting stuff.

+public:
+    void buildPropertyTrees(FrameView& rootFrame);
+
+private:
+    struct WalkContext;
+    struct WalkContextHTML;
+    struct WalkContextSVG;

[jbroman, 2015/10/14 15:11:58]

fwd declaring nonexistent struct

[trchen, 2015/10/14 22:51:13]

As discussed below. Let's have just one struct.

+
+    void walk(FrameView&, const WalkContext&);
+    void walk(LayoutBoxModelObject&, const WalkContextHTML&);
+};
+
+} // namespace blink
+
+#endif // PaintPropertyTreeBuilder_h