gh-14461: Fix boost size override not persisting (gh-14664)

src/zen/boosts/ZenBoostsEditor.mjs

@@ -659,7 +659,10 @@ ${cssSelector} {
       this.currentBoostData.sizeOverride = 0.9;
     } else if (this.currentBoostData.sizeOverride == 0.9) {
       this.currentBoostData.sizeOverride = 1;
-      await this.zenBoostsChild.sendQuery("ZenBoost:DisableSizeOverride");
+      await this.zenBoostsChild.updateBoostSizeOverride(
+        this.currentBoostData.sizeOverride,
+        /* disable: */ true
+      );
     }
 
     this.currentBoostData.changeWasMade = true;

src/zen/boosts/actors/ZenBoostsChild.sys.mjs

@@ -280,9 +280,6 @@ export class ZenBoostsChild extends JSWindowActorChild {
       case "ZenBoost:OpenInspector":
         this.sendAsyncMessage("ZenBoost:OpenInspector");
         break;
-      case "ZenBoost:DisableSizeOverride":
-        this.disableSizeOverride();
-        break;
     }
     return null;
   }
@@ -359,13 +356,9 @@ export class ZenBoostsChild extends JSWindowActorChild {
         this.#loadStyleSheet(boost.styleSheet);
       }
 
-      if (
-        boostData.sizeOverride &&
-        isFinite(boostData.sizeOverride) &&
-        boostData.sizeOverride !== 1
-      ) {
-        browsingContext.fullZoom = boostData.sizeOverride;
-      }
+      this.sendAsyncMessage("ZenBoost:UpdateBoostSize", {
+        sizeOverride: boostData.sizeOverride,
+      });
 
       browsingContext.isZenBoostsInverted = boostData.smartInvert;
       if (boostData.enableColorBoost) {
@@ -552,14 +545,6 @@ export class ZenBoostsChild extends JSWindowActorChild {
     this.sendNotify("selector-picker-state-update", "ondisable");
   }
 
-  disableSizeOverride() {
-    const browsingContext = this.browsingContext;
-    if (!browsingContext || browsingContext.parent !== null) {
-      return;
-    }
-    browsingContext.fullZoom = 1;
-  }
-
   sendNotify(topic, msg = null) {
     this.sendAsyncMessage("ZenBoost:Notify", { topic, msg });
   }

src/zen/boosts/actors/ZenBoostsParent.sys.mjs

@@ -72,6 +72,23 @@ export class ZenBoostsParent extends JSWindowActorParent {
     }
   }
 
+  /**
+   * Updates the boost size override on webpage
+   *
+   * @param {number} sizeOverride - The size to apply on the webpage as a override
+   * @param {boolean} disable - Whether to disable the override (sets override to the default 1)
+   */
+  updateBoostSizeOverride(sizeOverride, disable = false) {
+    if (
+      sizeOverride &&
+      isFinite(sizeOverride) &&
+      (sizeOverride !== 1 || disable)
+    ) {
+      const fullZoom = this.browsingContext.topChromeWindow.FullZoom;
+      fullZoom.setZoom(sizeOverride);
+    }
+  }
+
   /**
    * Handles messages received from child actors.
    * Retrieves boost data for a domain when requested.
@@ -174,6 +191,11 @@ export class ZenBoostsParent extends JSWindowActorParent {
             : null,
         };
       }
+      case "ZenBoost:UpdateBoostSize": {
+        const { sizeOverride } = message.data;
+        this.updateBoostSizeOverride(sizeOverride);
+        break;
+      }
       default: {
         console.warn(`[ZenBoostsParent]: Unknown message: ${message.name}`);
         break;