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

ash/common/shelf/shelf_layout_manager.cc

Index: ash/common/shelf/shelf_layout_manager.cc
diff --git a/ash/common/shelf/shelf_layout_manager.cc b/ash/common/shelf/shelf_layout_manager.cc
index a860a9b07a89cfe94134ed5f9772c838d9a9ab50..e307af958438b4d985ea1946e3dde512ab32f4e8 100644
--- a/ash/common/shelf/shelf_layout_manager.cc
+++ b/ash/common/shelf/shelf_layout_manager.cc
@@ -8,6 +8,7 @@
 #include <cmath>
 #include <vector>
 
+#include "ash/animation/animation_change_type.h"
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/session/session_controller.h"
 #include "ash/common/session/session_state_delegate.h"
@@ -96,7 +97,7 @@ class ShelfLayoutManager::UpdateShelfObserver
 
   void OnImplicitAnimationsCompleted() override {
     if (shelf_)
-      shelf_->MaybeUpdateShelfBackground(BACKGROUND_CHANGE_ANIMATE);
+      shelf_->MaybeUpdateShelfBackground(AnimationChangeType::ANIMATE);
     delete this;
   }
 
@@ -325,7 +326,7 @@ void ShelfLayoutManager::UpdateAutoHideForGestureEvent(ui::GestureEvent* event,
 
 void ShelfLayoutManager::SetWindowOverlapsShelf(bool value) {
   window_overlaps_shelf_ = value;
-  MaybeUpdateShelfBackground(BACKGROUND_CHANGE_ANIMATE);
+  MaybeUpdateShelfBackground(AnimationChangeType::ANIMATE);
 }
 
 void ShelfLayoutManager::AddObserver(ShelfLayoutManagerObserver* observer) {
@@ -500,7 +501,7 @@ void ShelfLayoutManager::SetState(ShelfVisibilityState visibility_state) {
   State old_state = state_;
   state_ = state;
 
-  BackgroundAnimatorChangeType change_type = BACKGROUND_CHANGE_ANIMATE;
+  AnimationChangeType change_type = AnimationChangeType::ANIMATE;
   bool delay_background_change = false;
 
   // Do not animate the background when:
@@ -511,7 +512,7 @@ void ShelfLayoutManager::SetState(ShelfVisibilityState visibility_state) {
   if (state.visibility_state == SHELF_VISIBLE &&
       state.window_state == wm::WORKSPACE_WINDOW_STATE_MAXIMIZED &&
       old_state.visibility_state != SHELF_VISIBLE) {
-    change_type = BACKGROUND_CHANGE_IMMEDIATE;
+    change_type = AnimationChangeType::IMMEDIATE;
   } else {
     // Delay the animation when the shelf was hidden, and has just been made
     // visible (e.g. using a gesture-drag).
@@ -814,8 +815,7 @@ void ShelfLayoutManager::UpdateTargetBoundsForGesture(
   }
 }
 
-void ShelfLayoutManager::MaybeUpdateShelfBackground(
-    BackgroundAnimatorChangeType type) {
+void ShelfLayoutManager::MaybeUpdateShelfBackground(AnimationChangeType type) {
   const ShelfBackgroundType new_background_type(GetShelfBackgroundType());
 
   if (new_background_type == shelf_background_type_)
@@ -981,7 +981,7 @@ void ShelfLayoutManager::OnDockBoundsChanging(
     dock_bounds_ = dock_bounds;
     OnWindowResized();
     UpdateVisibilityState();
-    MaybeUpdateShelfBackground(BACKGROUND_CHANGE_ANIMATE);
+    MaybeUpdateShelfBackground(AnimationChangeType::ANIMATE);
   }
 }
 
@@ -994,7 +994,7 @@ void ShelfLayoutManager::OnLockStateEvent(LockStateObserver::EventType event) {
   } else {
     state_.pre_lock_screen_animation_active = false;
   }
-  MaybeUpdateShelfBackground(BACKGROUND_CHANGE_ANIMATE);
+  MaybeUpdateShelfBackground(AnimationChangeType::ANIMATE);
 }
 
 void ShelfLayoutManager::SessionStateChanged(
@@ -1004,7 +1004,7 @@ void ShelfLayoutManager::SessionStateChanged(
   const bool was_adding_user = state_.IsAddingSecondaryUser();
   const bool was_locked = state_.IsScreenLocked();
   state_.session_state = state;
-  MaybeUpdateShelfBackground(BACKGROUND_CHANGE_ANIMATE);
+  MaybeUpdateShelfBackground(AnimationChangeType::ANIMATE);
   if (was_adding_user != state_.IsAddingSecondaryUser()) {
     UpdateShelfVisibilityAfterLoginUIChange();
     return;
@@ -1060,7 +1060,7 @@ void ShelfLayoutManager::StartGestureDrag(const ui::GestureEvent& gesture) {
   gesture_drag_auto_hide_state_ = visibility_state() == SHELF_AUTO_HIDE
                                       ? auto_hide_state()
                                       : SHELF_AUTO_HIDE_SHOWN;
-  MaybeUpdateShelfBackground(BACKGROUND_CHANGE_ANIMATE);
+  MaybeUpdateShelfBackground(AnimationChangeType::ANIMATE);
 }
 
 void ShelfLayoutManager::UpdateGestureDrag(const ui::GestureEvent& gesture) {