reland -- Disable animations during aura tests.

ui/gfx/compositor/layer_animation_sequence.h

Index: ui/gfx/compositor/layer_animation_sequence.h
diff --git a/ui/gfx/compositor/layer_animation_sequence.h b/ui/gfx/compositor/layer_animation_sequence.h
index 2fad33dff8e9ae7ebe2f0464516bf0bc9f40516f..a74bb77dc2181d37d3d2d8c7ae394edd17874715 100644
--- a/ui/gfx/compositor/layer_animation_sequence.h
+++ b/ui/gfx/compositor/layer_animation_sequence.h
@@ -65,6 +65,9 @@ class COMPOSITOR_EXPORT LayerAnimationSequence {
   void set_is_cyclic(bool is_cyclic) { is_cyclic_ = is_cyclic; }
   bool is_cyclic() const { return is_cyclic_; }
 
+  // Returns true if the sequence is currently animating.
+  bool is_animating() const { return is_animating_; }
+
   // Returns true if this sequence has at least one element affecting a
   // property in |other|.
   bool HasCommonProperty(
@@ -108,6 +111,9 @@ class COMPOSITOR_EXPORT LayerAnimationSequence {
   // True if the sequence should be looped forever.
   bool is_cyclic_;
 
+  // True if the sequence is currently animating.
+  bool is_animating_;
+
   // These are used when animating to efficiently find the next element.
   size_t last_element_;
   base::TimeDelta last_start_;