[reland] cros: OnHotseatTransitionStarted -> WillStart

Rename the observer to make it more clear that the function is called
prior to the animation beginning.

TBR=manucornet@chromium.org

Change-Id: I627bf805a74c12f86df5fb5bf4a85debaf9b63a0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2065337Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Commit-Queue: Alex Newcomer <newcomer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#743339}

ash/shelf/hotseat_transition_animator.cc

@@ -141,7 +141,7 @@ void HotseatTransitionAnimator::DoAnimation(HotseatState old_state,
   animation_metrics_reporter_->set_new_state(new_state);
 
   for (auto& observer : observers_)
-    observer.OnHotseatTransitionAnimationStarted(old_state, new_state);
+    observer.OnHotseatTransitionAnimationWillStart(old_state, new_state);
 
   {
     ui::ScopedLayerAnimationSettings shelf_bg_animation_setter(

ash/shelf/hotseat_transition_animator.h

@@ -30,9 +30,9 @@ class ASH_EXPORT HotseatTransitionAnimator
 
   class Observer : public base::CheckedObserver {
    public:
-    // Called before the hotseat transition animations begin.
-    virtual void OnHotseatTransitionAnimationStarted(HotseatState from_state,
-                                                     HotseatState to_start) {}
+    // Called before hotseat transition animations begin.
+    virtual void OnHotseatTransitionAnimationWillStart(HotseatState from_state,
+                                                       HotseatState to_start) {}
     // Called when hotseat transition animations end.
     virtual void OnHotseatTransitionAnimationEnded(HotseatState from_state,
                                                    HotseatState to_start) {}

ash/shelf/hotseat_widget.cc

@@ -112,8 +112,8 @@ class HotseatWidget::DelegateView : public HotseatTransitionAnimator::Observer,
   void SetBackgroundBlur(bool enable_blur);
 
   // HotseatTransitionAnimator::Observer:
-  void OnHotseatTransitionAnimationStarted(HotseatState from_state,
-                                           HotseatState to_state) override;
+  void OnHotseatTransitionAnimationWillStart(HotseatState from_state,
+                                             HotseatState to_state) override;
   void OnHotseatTransitionAnimationEnded(HotseatState from_state,
                                          HotseatState to_state) override;
   // views::WidgetDelegateView:
@@ -229,7 +229,7 @@ void HotseatWidget::DelegateView::SetBackgroundBlur(bool enable_blur) {
     translucent_background_.SetBackgroundBlur(blur_radius);
 }
 
-void HotseatWidget::DelegateView::OnHotseatTransitionAnimationStarted(
+void HotseatWidget::DelegateView::OnHotseatTransitionAnimationWillStart(
     HotseatState from_state,
     HotseatState to_state) {
   SetBackgroundBlur(false);

ash/shelf/shelf.cc

@@ -68,8 +68,8 @@ class HotseatWidgetAnimationMetricsReporter
 
   ~HotseatWidgetAnimationMetricsReporter() override {}
 
-  void OnHotseatTransitionAnimationStarted(HotseatState from_state,
-                                           HotseatState to_state) override {
+  void OnHotseatTransitionAnimationWillStart(HotseatState from_state,
+                                             HotseatState to_state) override {
     target_state_ = to_state;
   }
 

ash/shelf/shelf_widget.cc

@@ -152,8 +152,8 @@ class ShelfWidget::DelegateView : public views::WidgetDelegate,
   void UpdateShelfBackground(SkColor color) override;
 
   // HotseatBackgroundAnimator::Observer:
-  void OnHotseatTransitionAnimationStarted(HotseatState from_state,
-                                           HotseatState to_state) override;
+  void OnHotseatTransitionAnimationWillStart(HotseatState from_state,
+                                             HotseatState to_state) override;
   void OnHotseatTransitionAnimationEnded(HotseatState from_state,
                                          HotseatState to_state) override;
 
@@ -421,7 +421,7 @@ void ShelfWidget::DelegateView::UpdateShelfBackground(SkColor color) {
   UpdateOpaqueBackground();
 }
 
-void ShelfWidget::DelegateView::OnHotseatTransitionAnimationStarted(
+void ShelfWidget::DelegateView::OnHotseatTransitionAnimationWillStart(
     HotseatState from_state,
     HotseatState to_state) {
   ShowAnimatingBackground(true);