Use a bezier timing function for the overview mode animation

ui/gfx/geometry/cubic_bezier.h

Index: ui/gfx/geometry/cubic_bezier.h
diff --git a/ui/gfx/screen_type_delegate.h b/ui/gfx/geometry/cubic_bezier.h
similarity index 25%
copy from ui/gfx/screen_type_delegate.h
copy to ui/gfx/geometry/cubic_bezier.h
index 4d9f116aedd6f8dce1d8643a7b550879735bd738..4065d4469034e52c1cc8453e09b0ab74f0b2bd4f 100644
--- a/ui/gfx/screen_type_delegate.h
+++ b/ui/gfx/geometry/cubic_bezier.h
@@ -2,31 +2,35 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef UI_GFX_SCREEN_TYPE_DELEGATE_H_
-#define UI_GFX_SCREEN_TYPE_DELEGATE_H_
+#ifndef UI_GFX_GEOMETRY_CUBIC_BEZIER_H_

[sky, 2014/02/04 15:14:40]

nit: play with the --similarity so this isn't seen as a copy.

+#define UI_GFX_GEOMETRY_CUBIC_BEZIER_H_
 
-#include "ui/gfx/native_widget_types.h"
+#include "base/macros.h"
+#include "ui/gfx/gfx_export.h"
 
 namespace gfx {
 
-enum GFX_EXPORT ScreenType {
-  SCREEN_TYPE_NATIVE = 0,
-#if defined(OS_CHROMEOS)
-  SCREEN_TYPE_ALTERNATE = SCREEN_TYPE_NATIVE,
-#else
-  SCREEN_TYPE_ALTERNATE,
-#endif
-  SCREEN_TYPE_LAST = SCREEN_TYPE_ALTERNATE,
-};
-
-class GFX_EXPORT ScreenTypeDelegate {
+class GFX_EXPORT CubicBezier {
  public:
-  virtual ~ScreenTypeDelegate() {}
+  CubicBezier(double x1, double y1, double x2, double y2);
+  virtual ~CubicBezier();

[sky, 2014/02/04 15:14:40]

Why the virtual?

+
+  // Returns an approximation of y at the given x.
+  double Solve(double x) const;
+
+  // Sets |min| and |max| to the bezier's minimum and maximium y values in the
+  // interval [0, 1].
+  virtual void Range(double* min, double* max) const;
+
+ private:
+  double x1_;
+  double y1_;
+  double x2_;
+  double y2_;
 
-  // Determines which ScreenType a given |view| belongs to.
-  virtual ScreenType GetScreenTypeForNativeView(NativeView view) = 0;
+  DISALLOW_ASSIGN(CubicBezier);
 };
 
 }  // namespace gfx
 
-#endif  // UI_GFX_SCREEN_TYPE_DELEGATE_H_
+#endif  // UI_GFX_GEOMETRY_CUBIC_BEZIER_H_