cc: Support animating scroll offset

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 40b0be552ea9907a4fa9bf30cac1bcf60de8b073..63445d965dc8a5f5971d80285d7d4037602a51fa 100644
--- a/cc/animation/scroll_offset_animation_curve_unittest.cc
+++ b/cc/animation/scroll_offset_animation_curve_unittest.cc
@@ -11,16 +11,61 @@
 namespace cc {
 namespace {
 
+TEST(ScrollOffsetAnimationCurveTest, Duration) {
+  gfx::Vector2dF target_value(100.f, 200.f);
+  scoped_ptr<ScrollOffsetAnimationCurve> curve(
+      ScrollOffsetAnimationCurve::Create(
+          target_value,
+          EaseInOutTimingFunction::Create().Pass()));

[Ian Vollick, 2013/11/29 15:29:29]

Won't this need to be updated each time we tweak the formula for computing
duration?

[ajuma, 2013/11/29 21:18:41]

Yes, but I think it's still worth having, since there are a couple useful things
this test does: 1) It verifies that the duration does depend on both the
horizontal and vertical deltas. 2) It gives a rough idea of how the size of a
scroll translates into a duration (e.g. that tiny scrolls are getting tiny
durations, and larger scrolls are getting larger durations but not ridiculously
larger durations).

This shouldn't be too much of a burden to maintain; once the smooth scroll API
ships, it's unlikely that we'll change this very much (if at all).

+
+  curve->SetInitialValue(target_value);
+  EXPECT_DOUBLE_EQ(0.0, curve->Duration());
+
+  // x decreases, y stays the same.
+  curve->SetInitialValue(gfx::Vector2dF(136.f, 200.f));
+  EXPECT_DOUBLE_EQ(0.1, curve->Duration());
+
+  // x increases, y stays the same.
+  curve->SetInitialValue(gfx::Vector2dF(19.f, 200.f));
+  EXPECT_DOUBLE_EQ(0.15, curve->Duration());
+
+  // x stays the same, y decreases.
+  curve->SetInitialValue(gfx::Vector2dF(100.f, 344.f));
+  EXPECT_DOUBLE_EQ(0.2, curve->Duration());
+
+  // x stays the same, y increases.
+  curve->SetInitialValue(gfx::Vector2dF(100.f, 191.f));
+  EXPECT_DOUBLE_EQ(0.05, curve->Duration());
+
+  // x decreases, y decreases.
+  curve->SetInitialValue(gfx::Vector2dF(32500.f, 500.f));
+  EXPECT_DOUBLE_EQ(3.0, curve->Duration());
+
+  // x decreases, y increases.
+  curve->SetInitialValue(gfx::Vector2dF(150.f, 119.f));
+  EXPECT_DOUBLE_EQ(0.15, curve->Duration());
+
+  // x increases, y decreases.
+  curve->SetInitialValue(gfx::Vector2dF(0.f, 14600.f));
+  EXPECT_DOUBLE_EQ(2.0, curve->Duration());
+
+  // x increases, y increases.
+  curve->SetInitialValue(gfx::Vector2dF(95.f, 191.f));
+  EXPECT_DOUBLE_EQ(0.05, curve->Duration());
+}
+
 TEST(ScrollOffsetAnimationCurveTest, GetValue) {
   gfx::Vector2dF initial_value(2.f, 40.f);
   gfx::Vector2dF target_value(10.f, 20.f);
-  double duration = 10.0;
   scoped_ptr<ScrollOffsetAnimationCurve> curve(
       ScrollOffsetAnimationCurve::Create(
           target_value,
           EaseInOutTimingFunction::Create().Pass()));
-  curve->set_duration(duration);
-  curve->set_initial_value(initial_value);
+  curve->SetInitialValue(initial_value);
+
+  double duration = curve->Duration();
+  EXPECT_GT(curve->Duration(), 0);
+  EXPECT_LT(curve->Duration(), 0.1);
 
   EXPECT_EQ(AnimationCurve::ScrollOffset, curve->Type());
   EXPECT_EQ(duration, curve->Duration());
@@ -41,13 +86,12 @@ TEST(ScrollOffsetAnimationCurveTest, GetValue) {
 TEST(ScrollOffsetAnimationCurveTest, Clone) {
   gfx::Vector2dF initial_value(2.f, 40.f);
   gfx::Vector2dF target_value(10.f, 20.f);
-  double duration = 10.0;
   scoped_ptr<ScrollOffsetAnimationCurve> curve(
       ScrollOffsetAnimationCurve::Create(
           target_value,
           EaseInOutTimingFunction::Create().Pass()));
-  curve->set_duration(duration);
-  curve->set_initial_value(initial_value);
+  curve->SetInitialValue(initial_value);
+  double duration = curve->Duration();
 
   scoped_ptr<AnimationCurve> clone(curve->Clone().Pass());
 
@@ -75,6 +119,5 @@ TEST(ScrollOffsetAnimationCurveTest, Clone) {
   EXPECT_NEAR(37.4168f, value.y(), 0.00015f);
 }
 
-
 }  // namespace
 }  // namespace cc