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

ui/cc/cc/CCPageScaleAnimation.h

Index: ui/cc/cc/CCPageScaleAnimation.h
diff --git a/ui/cc/cc/CCPageScaleAnimation.h b/ui/cc/cc/CCPageScaleAnimation.h
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index 0000000000000000000000000000000000000000..d9acb4911dbc256ff9ebf9ea7e2d3ec33e6ff07d
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+++ b/ui/cc/cc/CCPageScaleAnimation.h
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+/*
+ * 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 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 CCPageScaleAnimation_h
+#define CCPageScaleAnimation_h
+
+#include "IntSize.h"
+#include <wtf/PassOwnPtr.h>
+
+namespace WebCore {
+
+// A small helper class that does the math for zoom animations, primarily for
+// double-tap zoom. Initialize it with starting and ending scroll/page scale
+// positions and an animation length time, then call ...AtTime() at every frame
+// to obtain the current interpolated position.
+class CCPageScaleAnimation {
+public:
+    // Construct with the starting page scale and scroll offset (which is in
+    // pageScaleStart space). The window size is the user-viewable area
+    // in pixels.
+    static PassOwnPtr<CCPageScaleAnimation> create(const IntSize& scrollStart, float pageScaleStart, const IntSize& windowSize, const IntSize& contentSize, double startTime);
+
+    // The following methods initialize the animation. Call one of them
+    // immediately after construction to set the final scroll and page scale.
+
+    // Zoom while explicitly specifying the top-left scroll position. The
+    // scroll offset is in finalPageScale coordinates.
+    void zoomTo(const IntSize& finalScroll, float finalPageScale, double duration);
+
+    // Zoom based on a specified onscreen anchor, which will remain at the same
+    // position on the screen throughout the animation. The anchor is in local
+    // space relative to scrollStart.
+    void zoomWithAnchor(const IntSize& anchor, float finalPageScale, double duration);
+
+    // Call these functions while the animation is in progress to output the
+    // current state.
+    IntSize scrollOffsetAtTime(double time) const;
+    float pageScaleAtTime(double time) const;
+    bool isAnimationCompleteAtTime(double time) const;
+
+    // The following methods return state which is invariant throughout the
+    // course of the animation.
+    double startTime() const { return m_startTime; }
+    double duration() const { return m_duration; }
+    double endTime() const { return m_startTime + m_duration; }
+    const IntSize& finalScrollOffset() const { return m_scrollEnd; }
+    float finalPageScale() const { return m_pageScaleEnd; }
+
+protected:
+    CCPageScaleAnimation(const IntSize& scrollStart, float pageScaleStart, const IntSize& windowSize, const IntSize& contentSize, double startTime);
+
+private:
+    float progressRatioForTime(double time) const;
+    IntSize scrollOffsetAtRatio(float ratio) const;
+    float pageScaleAtRatio(float ratio) const;
+
+    IntSize m_scrollStart;
+    float m_pageScaleStart;
+    IntSize m_windowSize;
+    IntSize m_contentSize;
+
+    bool m_anchorMode;
+    IntSize m_anchor;
+    IntSize m_scrollEnd;
+    float m_pageScaleEnd;
+
+    double m_startTime;
+    double m_duration;
+};
+
+} // namespace WebCore
+
+#endif