Initial import attempt, just to play with. Many things disabled/removed

ui/cc/cc/CCDamageTracker.h

Index: ui/cc/cc/CCDamageTracker.h
diff --git a/ui/cc/cc/CCDamageTracker.h b/ui/cc/cc/CCDamageTracker.h
new file mode 100644
index 0000000000000000000000000000000000000000..8d6a2ee8dae85dbf32f75511bafb083aca1822be
--- /dev/null
+++ b/ui/cc/cc/CCDamageTracker.h
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2011 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef CCDamageTracker_h
+#define CCDamageTracker_h
+
+#include "FloatRect.h"
+#include <wtf/HashMap.h>
+#include <wtf/PassOwnPtr.h>
+#include <wtf/Vector.h>
+
+namespace WebKit {
+class WebFilterOperations;
+}
+
+namespace WebCore {
+
+class CCLayerImpl;
+class CCRenderSurface;
+
+// Computes the region where pixels have actually changed on a RenderSurface. This region is used
+// to scissor what is actually drawn to the screen to save GPU computation and bandwidth.
+class CCDamageTracker {
+public:
+    static PassOwnPtr<CCDamageTracker> create();
+    ~CCDamageTracker();
+
+    void didDrawDamagedArea() { m_currentDamageRect = FloatRect(); }
+    void forceFullDamageNextUpdate() { m_forceFullDamageNextUpdate = true; }
+    void updateDamageTrackingState(const Vector<CCLayerImpl*>& layerList, int targetSurfaceLayerID, bool targetSurfacePropertyChangedOnlyFromDescendant, const IntRect& targetSurfaceContentRect, CCLayerImpl* targetSurfaceMaskLayer, const WebKit::WebFilterOperations&);
+
+    const FloatRect& currentDamageRect() { return m_currentDamageRect; }
+
+private:
+    CCDamageTracker();
+
+    FloatRect trackDamageFromActiveLayers(const Vector<CCLayerImpl*>& layerList, int targetSurfaceLayerID);
+    FloatRect trackDamageFromSurfaceMask(CCLayerImpl* targetSurfaceMaskLayer);
+    FloatRect trackDamageFromLeftoverRects();
+
+    FloatRect removeRectFromCurrentFrame(int layerID, bool& layerIsNew);
+    void saveRectForNextFrame(int layerID, const FloatRect& targetSpaceRect);
+
+    // These helper functions are used only in trackDamageFromActiveLayers().
+    void extendDamageForLayer(CCLayerImpl*, FloatRect& targetDamageRect);
+    void extendDamageForRenderSurface(CCLayerImpl*, FloatRect& targetDamageRect);
+
+    // To correctly track exposed regions, two hashtables of rects are maintained.
+    // The "current" map is used to compute exposed regions of the current frame, while
+    // the "next" map is used to collect layer rects that are used in the next frame.
+    struct RectMapKeyTraits : HashTraits<int> {
+        static const bool emptyValueIsZero = false;
+        static const bool needsDestruction = false;
+        static int emptyValue() { return -1; }
+        static void constructDeletedValue(int& slot) { slot = -2; }
+        static bool isDeletedValue(int value) { return value == -2; }
+    };
+    typedef HashMap<int, FloatRect, DefaultHash<int>::Hash, RectMapKeyTraits> RectMap;
+    OwnPtr<RectMap> m_currentRectHistory;
+    OwnPtr<RectMap> m_nextRectHistory;
+
+    FloatRect m_currentDamageRect;
+    bool m_forceFullDamageNextUpdate;
+};
+
+} // namespace WebCore
+
+#endif // CCDamageTracker_h