Move fling implementation from renderer to browser:

content/browser/renderer_host/input/fling/fling_curve.h

+// Copyright 2013 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 CONTENT_BROWSER_RENDERER_HOST_INPUT_FLING_FLING_CURVE_H_
+#define CONTENT_BROWSER_RENDERER_HOST_INPUT_FLING_FLING_CURVE_H_
+
+#include "content/common/content_export.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
+
+namespace content {
+
+class CONTENT_EXPORT FlingCurveTarget {
+ public:
+  virtual void ScrollBy(const gfx::PointF& delta) = 0;
+  virtual void NotifyCurrentFlingVelocity(const gfx::PointF& velocity) = 0;
+
+ protected:
+  virtual ~FlingCurveTarget() { }
+};
+
+// Abstract interface for curves used by Flinger. A FlingCurve defines the
+// animation parameters as a function of time (zero-based), and applies the
+// parameters directly to the target of the animation.
+class CONTENT_EXPORT FlingCurve {
+ public:
+  virtual ~FlingCurve() {}
+
+  static FlingCurve* Create(blink::WebGestureEvent::SourceDevice source,
+                            const gfx::PointF& velocity,
+                            const gfx::Point& cumulative_scroll);
+
+  // Returns false if curve has finished and can no longer be applied.
+  virtual bool Apply(double time_in_secs, FlingCurveTarget*) = 0;
+};
+
+}  // namespace content
+
+#endif // CONTENT_BROWSER_RENDERER_HOST_INPUT_FLING_FLING_CURVE_H_