New paint invalidation using paint property tree walk

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

Index: third_party/WebKit/Source/core/paint/PrePaintTreeWalk.h
diff --git a/third_party/WebKit/Source/core/paint/PrePaintTreeWalk.h b/third_party/WebKit/Source/core/paint/PrePaintTreeWalk.h
new file mode 100644
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+++ b/third_party/WebKit/Source/core/paint/PrePaintTreeWalk.h
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+// 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 PrePaintTreeWalk_h
+#define PrePaintTreeWalk_h
+
+#include "wtf/Vector.h"
+
+namespace blink {
+
+class FrameView;
+class LayoutObject;
+class PaintInvalidationState;
+struct PrePaintTreeWalkContext;
+
+// This class walks layout and frame trees in primary tree order (think DOM order),
+// beginning from the root FrameView and acrossing frame boundaries. The walk is
+// used to create paint property tree nodes for layout & frame properties such as
+// clips and transforms. It should be invoked after layout, during
+// InPrePaintTreeWalk document lifecycle state.
+//
+// If RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled, we also invalidate
+// paint along the way.
+class PrePaintTreeWalk {
+public:
+    void buildPropertyTreesAndInvalidatePaint(FrameView& rootFrame);
+
+    // Objects requiring invalidation after the phase of paint invalidation.
+    // See the definition of PaintInvalidationDelayedFull (PaintInvalidationReason.h) for more detail.
+    const Vector<LayoutObject*>& pendingDelayedPaintInvalidations() const { return m_pendingDelayedPaintInvalidations; }
+
+private:
+    void walk(FrameView&, const PrePaintTreeWalkContext&, const PaintInvalidationState*);
+    void walk(const LayoutObject&, const PrePaintTreeWalkContext&, const PaintInvalidationState*);
+
+    Vector<LayoutObject*> m_pendingDelayedPaintInvalidations;
+};
+
+} // namespace blink
+
+#endif // PrePaintTreeWalk_h