[gnome-shell/wip/carlosg/grabs-pt2: 7/9] grabHelper: Use Clutter.grab() underneath

[Carlos Garnacho <carlosg src gnome org>]

commit 58a1086e2b9da00478ee9e1a333d84fe14dee9e7
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Nov 18 00:56:44 2021 +0100

    grabHelper: Use Clutter.grab() underneath
    
    This is subject to further possible simplifications. Use Clutter.grab
    to redirect input and focus, a fundamental difference here is that
    we do redirect input to the topmost owner of the grabhelper stack,
    instead of the stage. This is better behaved with the presence of
    other grabs, at the cost of some behavioral changes.

 js/ui/grabHelper.js | 33 +++++----------------------------
 1 file changed, 5 insertions(+), 28 deletions(-)
---
diff --git a/js/ui/grabHelper.js b/js/ui/grabHelper.js
index e70285bdee..89e1bee321 100644
--- a/js/ui/grabHelper.js
+++ b/js/ui/grabHelper.js
@@ -6,31 +6,6 @@ const { Clutter, St } = imports.gi;
 const Main = imports.ui.main;
 const Params = imports.misc.params;
 
-let _capturedEventId = 0;
-let _grabHelperStack = [];
-function _onCapturedEvent(actor, event) {
-    let grabHelper = _grabHelperStack[_grabHelperStack.length - 1];
-    return grabHelper.onCapturedEvent(event);
-}
-
-function _pushGrabHelper(grabHelper) {
-    _grabHelperStack.push(grabHelper);
-
-    if (_capturedEventId == 0)
-        _capturedEventId = global.stage.connect('captured-event', _onCapturedEvent);
-}
-
-function _popGrabHelper(grabHelper) {
-    let poppedHelper = _grabHelperStack.pop();
-    if (poppedHelper != grabHelper)
-        throw new Error("incorrect grab helper pop");
-
-    if (_grabHelperStack.length == 0) {
-        global.stage.disconnect(_capturedEventId);
-        _capturedEventId = 0;
-    }
-}
-
 // GrabHelper:
 // @owner: the actor that owns the GrabHelper
 // @params: optional parameters to pass to Main.pushModal()
@@ -209,7 +184,10 @@ var GrabHelper = class GrabHelper {
             if (!Main.pushModal(this._owner, this._modalParams))
                 return false;
 
-            _pushGrabHelper(this);
+            this._capturedEventId = this._owner.connect('captured-event',
+                (actor, event) => {
+                    return this.onCapturedEvent(event);
+                });
         }
 
         this._modalCount++;
@@ -221,8 +199,7 @@ var GrabHelper = class GrabHelper {
         if (this._modalCount > 0)
             return;
 
-        _popGrabHelper(this);
-
+        this._owner.disconnect(this._capturedEventId);
         this._ignoreUntilRelease = false;
 
         Main.popModal(this._owner);