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

ui/cc/cc/CCOverdrawMetrics.h

Index: ui/cc/cc/CCOverdrawMetrics.h
diff --git a/ui/cc/cc/CCOverdrawMetrics.h b/ui/cc/cc/CCOverdrawMetrics.h
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+++ b/ui/cc/cc/CCOverdrawMetrics.h
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+/*
+ * Copyright (C) 2012 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 INC. 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 INC. 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 CCOverdrawMetrics_h
+#define CCOverdrawMetrics_h
+
+#include <wtf/PassOwnPtr.h>
+
+namespace WebKit {
+class WebTransformationMatrix;
+}
+
+namespace WebCore {
+class IntRect;
+class CCLayerTreeHost;
+class CCLayerTreeHostImpl;
+
+// FIXME: compute overdraw metrics only occasionally, not every frame.
+class CCOverdrawMetrics {
+public:
+    static PassOwnPtr<CCOverdrawMetrics> create(bool recordMetricsForFrame) { return adoptPtr(new CCOverdrawMetrics(recordMetricsForFrame)); }
+
+    // These methods are used for saving metrics during update/commit.
+
+    // Record pixels painted by WebKit into the texture updater, but does not mean the pixels were rasterized in main memory.
+    void didPaint(const IntRect& paintedRect);
+    // Records that an invalid tile was culled and did not need to be painted/uploaded, and did not contribute to other tiles needing to be painted.
+    void didCullTileForUpload();
+    // Records pixels that were uploaded to texture memory.
+    void didUpload(const WebKit::WebTransformationMatrix& transformToTarget, const IntRect& uploadRect, const IntRect& opaqueRect);
+
+    // These methods are used for saving metrics during draw.
+
+    // Record pixels that were not drawn to screen.
+    void didCullForDrawing(const WebKit::WebTransformationMatrix& transformToTarget, const IntRect& beforeCullRect, const IntRect& afterCullRect);
+    // Record pixels that were drawn to screen.
+    void didDraw(const WebKit::WebTransformationMatrix& transformToTarget, const IntRect& afterCullRect, const IntRect& opaqueRect);
+
+    void recordMetrics(const CCLayerTreeHost*) const;
+    void recordMetrics(const CCLayerTreeHostImpl*) const;
+
+    // Accessors for tests.
+    float pixelsDrawnOpaque() const { return m_pixelsDrawnOpaque; }
+    float pixelsDrawnTranslucent() const { return m_pixelsDrawnTranslucent; }
+    float pixelsCulledForDrawing() const { return m_pixelsCulledForDrawing; }
+    float pixelsPainted() const { return m_pixelsPainted; }
+    float pixelsUploadedOpaque() const { return m_pixelsUploadedOpaque; }
+    float pixelsUploadedTranslucent() const { return m_pixelsUploadedTranslucent; }
+    int tilesCulledForUpload() const { return m_tilesCulledForUpload; }
+
+private:
+    enum MetricsType {
+        UpdateAndCommit,
+        DrawingToScreen
+    };
+
+    explicit CCOverdrawMetrics(bool recordMetricsForFrame);
+
+    template<typename LayerTreeHostType>
+    void recordMetricsInternal(MetricsType, const LayerTreeHostType*) const;
+
+    // When false this class is a giant no-op.
+    bool m_recordMetricsForFrame;
+
+    // These values are used for saving metrics during update/commit.
+
+    // Count of pixels that were painted due to invalidation.
+    float m_pixelsPainted;
+    // Count of pixels uploaded to textures and known to be opaque.
+    float m_pixelsUploadedOpaque;
+    // Count of pixels uploaded to textures and not known to be opaque.
+    float m_pixelsUploadedTranslucent;
+    // Count of tiles that were invalidated but not uploaded.
+    int m_tilesCulledForUpload;
+
+    // These values are used for saving metrics during draw.
+
+    // Count of pixels that are opaque (and thus occlude). Ideally this is no more than wiewport width x height.
+    float m_pixelsDrawnOpaque;
+    // Count of pixels that are possibly translucent, and cannot occlude.
+    float m_pixelsDrawnTranslucent;
+    // Count of pixels not drawn as they are occluded by somthing opaque.
+    float m_pixelsCulledForDrawing;
+};
+
+} // namespace WebCore
+
+#endif