Scroll offset animation curve retargeting.

cc/animation/scroll_offset_animation_curve_unittest.cc

Index: cc/animation/scroll_offset_animation_curve_unittest.cc
diff --git a/cc/animation/scroll_offset_animation_curve_unittest.cc b/cc/animation/scroll_offset_animation_curve_unittest.cc
index 63445d965dc8a5f5971d80285d7d4037602a51fa..1b8fdb5467c0ad4c4fc8a50f2d7c060f38fcaca9 100644
--- a/cc/animation/scroll_offset_animation_curve_unittest.cc
+++ b/cc/animation/scroll_offset_animation_curve_unittest.cc
@@ -119,5 +119,30 @@ TEST(ScrollOffsetAnimationCurveTest, Clone) {
   EXPECT_NEAR(37.4168f, value.y(), 0.00015f);
 }
 
+TEST(ScrollOffsetAnimationCurveTest, UpdateTarget) {
+  gfx::Vector2dF initial_value(0.f, 0.f);
+  gfx::Vector2dF target_value(0.f, 3600.f);
+  scoped_ptr<ScrollOffsetAnimationCurve> curve(
+      ScrollOffsetAnimationCurve::Create(
+          target_value, EaseInOutTimingFunction::Create().Pass()));
+  curve->SetInitialValue(initial_value);
+  EXPECT_EQ(1.0, curve->Duration());
+  EXPECT_EQ(1800.0, curve->GetValue(0.5).y());
+  EXPECT_EQ(3600.0, curve->GetValue(1.0).y());
+
+  curve->UpdateTarget(0.5, gfx::Vector2dF(0.0, 9900.0));
+
+  EXPECT_EQ(2.0, curve->Duration());
+  EXPECT_EQ(1800.0, curve->GetValue(0.5).y());
+  EXPECT_NEAR(5566.49, curve->GetValue(1.0).y(), 0.01);
+  EXPECT_EQ(9900.0, curve->GetValue(2.0).y());
+
+  curve->UpdateTarget(1.0, gfx::Vector2dF(0.0, 7200.0));
+
+  EXPECT_NEAR(1.674, curve->Duration(), 0.01);
+  EXPECT_NEAR(5566.49, curve->GetValue(1.0).y(), 0.01);
+  EXPECT_EQ(7200.0, curve->GetValue(1.674).y());
+}
+
 }  // namespace
 }  // namespace cc