[ash-md] Remove the number of animators used for the Shelf animations.

ui/gfx/animation/slide_animation_unittest.cc

Index: ui/gfx/animation/slide_animation_unittest.cc
diff --git a/ui/gfx/animation/slide_animation_unittest.cc b/ui/gfx/animation/slide_animation_unittest.cc
index b22dab77ca9279481e3c72384f3833d9f3dcae00..9eb88d286034908cfb00239d4af5a81d8fac85fd 100644
--- a/ui/gfx/animation/slide_animation_unittest.cc
+++ b/ui/gfx/animation/slide_animation_unittest.cc
@@ -41,7 +41,7 @@ class SlideAnimationTest: public testing::Test {
 
 // Tests animation construction.
 TEST_F(SlideAnimationTest, InitialState) {
-  SlideAnimation animation(NULL);
+  SlideAnimation animation(nullptr);
   // By default, slide animations are 60 Hz, so the timer interval should be
   // 1/60th of a second.
   EXPECT_EQ(1000 / 60, animation.timer_interval().InMilliseconds());
@@ -55,7 +55,7 @@ TEST_F(SlideAnimationTest, InitialState) {
 }
 
 TEST_F(SlideAnimationTest, Basics) {
-  SlideAnimation animation(NULL);
+  SlideAnimation animation(nullptr);
   SlideAnimation::TestApi test_api(&animation);
 
   // Use linear tweening to make the math easier below.