athena: Add support for fling-scroll in overview mode.

ui/events/fling_curve_unittest.cc

+// Copyright 2014 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.
+
+#include "ui/events/fling_curve.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/gfx/frame_time.h"
+
+namespace ui {
+
+TEST(FlingCurveTest, Basic) {
+  const gfx::Vector2dF velocity(0, 5000);
+  base::TimeTicks now = gfx::FrameTime::Now();
+  FlingCurve curve(velocity, now);
+
+  gfx::Vector2dF scroll =
+      curve.GetScrollAmountAtTime(now + base::TimeDelta::FromMilliseconds(20));
+  EXPECT_EQ(0, scroll.x());
+  EXPECT_NEAR(scroll.y(), 96, 1);
+
+  scroll =
+      curve.GetScrollAmountAtTime(now + base::TimeDelta::FromMilliseconds(250));
+  EXPECT_EQ(0, scroll.x());
+  EXPECT_NEAR(scroll.y(), 705, 1);
+}
+
+}  // namespace ui