[WIP] Adding support for <iframe>s to slimming paint.

Source/core/paint/TranslationRecorder.h

+// Copyright 2014 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 TranslationRecorder_h
+#define TranslationRecorder_h
+
+#include "core/paint/ViewDisplayList.h"
+#include "platform/geometry/FloatSize.h"
+
+namespace blink {
+
+class GraphicsContext;
+class RenderObject;
+
+class TranslationDisplayItem : public DisplayItem {
+public:
+    TranslationDisplayItem(const FloatSize& translation)
+        // FIXME: Need proper identifier for this display item.
+        : DisplayItem(nullptr, Translation), m_translation(translation) { }
+
+private:
+    virtual void replay(GraphicsContext*) override;
+
+    FloatSize m_translation;
+};
+
+class EndTranslationDisplayItem : public TranslationDisplayItem {
+public:
+    EndTranslationDisplayItem(const FloatSize& translation) : TranslationDisplayItem(-translation) { }
+};
+
+class TranslationRecorder {
+public:
+    explicit TranslationRecorder(RenderObject*, GraphicsContext*, const FloatSize& translation);
+    ~TranslationRecorder();
+
+private:
+    RenderObject* m_renderer;
+    GraphicsContext* m_context;
+    FloatSize m_translation;
+};
+
+} // namespace blink
+
+#endif // TranslationRecorder_h