Update from https://crrev.com/304121

cc/animation/layer_animation_controller.cc

Index: cc/animation/layer_animation_controller.cc
diff --git a/cc/animation/layer_animation_controller.cc b/cc/animation/layer_animation_controller.cc
index b779a37957a8d165d517e611f0ee37da334bc963..f621ad318c4d5470442b842be7fee9ab4eee0333 100644
--- a/cc/animation/layer_animation_controller.cc
+++ b/cc/animation/layer_animation_controller.cc
@@ -148,7 +148,8 @@ void LayerAnimationController::AccumulatePropertyUpdates(
     if (!animation->InEffect(monotonic_time))
       continue;
 
-    double trimmed = animation->TrimTimeToCurrentIteration(monotonic_time);
+    double trimmed =
+        animation->TrimTimeToCurrentIteration(monotonic_time).InSecondsF();
     switch (animation->target_property()) {
       case Animation::Opacity: {
         AnimationEvent event(AnimationEvent::PropertyUpdate,
@@ -212,7 +213,11 @@ void LayerAnimationController::UpdateState(bool start_ready_animations,
   if (!HasActiveValueObserver())
     return;
 
-  DCHECK(last_tick_time_ != base::TimeTicks());
+  // Animate hasn't been called, this happens if an observer has been added
+  // between the Commit and Draw phases.
+  if (last_tick_time_ == base::TimeTicks())
+    return;
+
   if (start_ready_animations)
     PromoteStartedAnimations(last_tick_time_, events);
 
@@ -856,8 +861,9 @@ void LayerAnimationController::TickAnimations(base::TimeTicks monotonic_time) {
       if (!animations_[i]->InEffect(monotonic_time))
         continue;
 
-      double trimmed =
-          animations_[i]->TrimTimeToCurrentIteration(monotonic_time);
+      double trimmed = animations_[i]
+                           ->TrimTimeToCurrentIteration(monotonic_time)
+                           .InSecondsF();
 
       switch (animations_[i]->target_property()) {
         case Animation::Transform: {