Introduce NON_ZERO_DURATION for animation unit tests

ui/compositor/layer_animation_element.cc

Index: ui/compositor/layer_animation_element.cc
diff --git a/ui/compositor/layer_animation_element.cc b/ui/compositor/layer_animation_element.cc
index c25e4a1dc9647ad3de449f74c24353fe89351582..290b86537fafea9bc4e11763c5af621afc51cebc 100644
--- a/ui/compositor/layer_animation_element.cc
+++ b/ui/compositor/layer_animation_element.cc
@@ -20,11 +20,11 @@ namespace ui {
 
 namespace {
 
-// The factor by which duration is scaled up or down when
-// ScopedAnimationDurationScaleMode::duration_scale_mode() is SLOW_DURATION or
-// FAST_DURATION.
-const int kSlowDurationScaleFactor = 4;
-const int kFastDurationScaleFactor = 4;
+// The factor by which duration is scaled up or down when using
+// ScopedAnimationDurationScaleMode.
+const int kSlowDurationScaleMultiplier = 4;
+const int kFastDurationScaleDivisor = 4;
+const int kTestDurationScaleDivisor = 100;
 
 // Pause -----------------------------------------------------------------------
 class Pause : public LayerAnimationElement {
@@ -761,9 +761,11 @@ base::TimeDelta LayerAnimationElement::GetEffectiveDuration(
     case ScopedAnimationDurationScaleMode::NORMAL_DURATION:
       return duration;
     case ScopedAnimationDurationScaleMode::FAST_DURATION:
-      return duration / kFastDurationScaleFactor;
+      return duration / kFastDurationScaleDivisor;
     case ScopedAnimationDurationScaleMode::SLOW_DURATION:
-      return duration * kSlowDurationScaleFactor;
+      return duration * kSlowDurationScaleMultiplier;
+    case ScopedAnimationDurationScaleMode::NON_ZERO_DURATION:
+      return duration / kTestDurationScaleDivisor;
     case ScopedAnimationDurationScaleMode::ZERO_DURATION:
       return base::TimeDelta();
     default: