CC: Fix issue for animations with fill and iteration start specified

cc/animation/animation_unittest.cc

Index: cc/animation/animation_unittest.cc
diff --git a/cc/animation/animation_unittest.cc b/cc/animation/animation_unittest.cc
index 7b701784f8246cbcdb3bbf3e94ebbdf44fe0940a..b1592d690f4ba6aa36c2f4608b6fde4af280172c 100644
--- a/cc/animation/animation_unittest.cc
+++ b/cc/animation/animation_unittest.cc
@@ -619,6 +619,7 @@ TEST(AnimationTest,
 TEST(AnimationTest, TrimTimeIterationStart) {
   scoped_ptr<Animation> anim(CreateAnimation(2, 1, 1));
   anim->set_iteration_start(0.5);
+  EXPECT_EQ(0.5, anim->TrimTimeToCurrentIteration(TicksFromSecondsF(-1.0)));
   EXPECT_EQ(0.5, anim->TrimTimeToCurrentIteration(TicksFromSecondsF(0.0)));
   EXPECT_EQ(0.0, anim->TrimTimeToCurrentIteration(TicksFromSecondsF(0.5)));
   EXPECT_EQ(0.5, anim->TrimTimeToCurrentIteration(TicksFromSecondsF(1.0)));
@@ -631,6 +632,7 @@ TEST(AnimationTest, TrimTimeIterationStartAlternate) {
   scoped_ptr<Animation> anim(CreateAnimation(2, 1, 1));
   anim->set_direction(Animation::Alternate);
   anim->set_iteration_start(0.3);
+  EXPECT_EQ(0.3, anim->TrimTimeToCurrentIteration(TicksFromSecondsF(-1.0)));
   EXPECT_EQ(0.3, anim->TrimTimeToCurrentIteration(TicksFromSecondsF(0.0)));
   EXPECT_EQ(0.8, anim->TrimTimeToCurrentIteration(TicksFromSecondsF(0.5)));
   EXPECT_EQ(1.0, anim->TrimTimeToCurrentIteration(TicksFromSecondsF(0.7)));
@@ -643,6 +645,7 @@ TEST(AnimationTest, TrimTimeIterationStartAlternateThreeIterations) {
   scoped_ptr<Animation> anim(CreateAnimation(3, 1, 1));
   anim->set_direction(Animation::Alternate);
   anim->set_iteration_start(1);
+  EXPECT_EQ(1.0, anim->TrimTimeToCurrentIteration(TicksFromSecondsF(-1.0)));
   EXPECT_EQ(1.0, anim->TrimTimeToCurrentIteration(TicksFromSecondsF(0.0)));
   EXPECT_EQ(0.5, anim->TrimTimeToCurrentIteration(TicksFromSecondsF(0.5)));
   EXPECT_EQ(0.0, anim->TrimTimeToCurrentIteration(TicksFromSecondsF(1.0)));