Implement clip and scroll DisplayItems for PartPainter

Source/core/paint/RoundedInnerRectClipper.h

Index: Source/core/paint/RoundedInnerRectClipper.h
diff --git a/Source/core/paint/RoundedInnerRectClipper.h b/Source/core/paint/RoundedInnerRectClipper.h
new file mode 100644
index 0000000000000000000000000000000000000000..a21114d9d22c89b991978db685f68aa937a3d3df
--- /dev/null
+++ b/Source/core/paint/RoundedInnerRectClipper.h
@@ -0,0 +1,35 @@
+// 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 RoundedInnerRectClipper_h
+#define RoundedInnerRectClipper_h
+
+#include "core/rendering/PaintPhase.h"
+
+namespace blink {
+
+class FloatRoundedRect;
+class LayoutRect;
+class RenderObject;
+struct PaintInfo;
+
+enum RoundedInnerRectClipperBehavior {
+    ApplyToDisplayListIfEnabled,
+    ApplyToContext
+};
+
+class RoundedInnerRectClipper {
+public:
+    RoundedInnerRectClipper(RenderObject&, const PaintInfo&, const LayoutRect&, const FloatRoundedRect& clipRect, RoundedInnerRectClipperBehavior);
+    ~RoundedInnerRectClipper();
+
+private:
+    RenderObject& m_renderer;
+    const PaintInfo& m_paintInfo;
+    RoundedInnerRectClipperBehavior m_behavior;
+};
+
+} // namespace blink
+
+#endif // RoundedInnerRectClipper_h