overview: Reorganize animateTo/FromOverview()

Instead of directly accessing ViewSelector and calling these methods
there, cascade the calls to OverviewActor, ControlsManager, and finally
ViewSelector. Also move the opacity transition to OverviewActor.

This commit has no functional change.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1624>

js/ui/overview.js

@@ -97,6 +97,35 @@ class OverviewActor extends St.BoxLayout {
         this.add_child(this._controls);
     }
 
+    animateToOverview(callback) {
+        this._controls.animateToOverview();
+
+        this.opacity = 0;
+        this.ease({
+            opacity: 255,
+            mode: Clutter.AnimationMode.EASE_OUT_QUAD,
+            duration: ANIMATION_TIME,
+            onStopped: () => {
+                if (callback)
+                    callback();
+            },
+        });
+    }
+
+    animateFromOverview(callback) {
+        this._controls.animateFromOverview();
+
+        this.ease({
+            opacity: 0,
+            mode: Clutter.AnimationMode.EASE_OUT_QUAD,
+            duration: ANIMATION_TIME,
+            onStopped: () => {
+                if (callback)
+                    callback();
+            },
+        });
+    }
+
     get dash() {
         return this._controls.dash;
     }
@@ -492,15 +521,8 @@ var Overview = class {
         this._activationTime = GLib.get_monotonic_time() / GLib.USEC_PER_SEC;
 
         Meta.disable_unredirect_for_display(global.display);
-        this.viewSelector.animateToOverview();
 
-        this._overview.opacity = 0;
+        this._overview.animateToOverview(() => this._showDone());
-        this._overview.ease({
-            opacity: 255,
-            mode: Clutter.AnimationMode.EASE_OUT_QUAD,
-            duration: ANIMATION_TIME,
-            onComplete: () => this._showDone(),
-        });
 
         Main.layoutManager.overviewGroup.set_child_above_sibling(
             this._coverPane, null);
@@ -555,15 +577,7 @@ var Overview = class {
         this._animationInProgress = true;
         this._visibleTarget = false;
 
-        this.viewSelector.animateFromOverview();
+        this._overview.animateFromOverview(() => this._hideDone());
-
-        // Make other elements fade out.
-        this._overview.ease({
-            opacity: 0,
-            mode: Clutter.AnimationMode.EASE_OUT_QUAD,
-            duration: ANIMATION_TIME,
-            onComplete: () => this._hideDone(),
-        });
 
         Main.layoutManager.overviewGroup.set_child_above_sibling(
             this._coverPane, null);

js/ui/overviewControls.js

@@ -172,6 +172,14 @@ class ControlsManager extends St.Widget {
         this._workspaceAdjustment.value = activeIndex;
     }
 
+    animateToOverview() {
+        this.viewSelector.animateToOverview();
+    }
+
+    animateFromOverview() {
+        this.viewSelector.animateFromOverview();
+    }
+
     get searchEntry() {
         return this._searchEntry;
     }