Bug 1377845 - Fix TypeError: frame is undefined when resizing sub-dialog window r=MattN,scottwu

MozReview-Commit-ID: HjiaIyZHgkL

--HG--
extra : rebase_source : 6fe2382f6707925637f4e001b203574195c35751

browser/components/preferences/in-content-new/subdialogs.js

@@ -328,6 +328,7 @@ SubDialog.prototype = {
     this._overlay.style.opacity = ""; // XXX: focus hack continued from _onContentLoaded
 
     if (this._box.getAttribute("resizable") == "true") {
+      this._onResize = this._onResize.bind(this);
       this._resizeObserver = new MutationObserver(this._onResize);
       this._resizeObserver.observe(this._box, {attributes: true});
     }

browser/components/preferences/in-content/subdialogs.js

@@ -328,6 +328,7 @@ SubDialog.prototype = {
     this._overlay.style.opacity = ""; // XXX: focus hack continued from _onContentLoaded
 
     if (this._box.getAttribute("resizable") == "true") {
+      this._onResize = this._onResize.bind(this);
       this._resizeObserver = new MutationObserver(this._onResize);
       this._resizeObserver.observe(this._box, {attributes: true});
     }