[global] Remaps self.Common.settings

This CL changes references to self.Common.settings (the global
instance of SDK.Common.Settings) over to
Common.Settings.Settings.instance(). To keep both TypeScript and
Closure happy we must make a method on the Settings class itself,
since it only allows private constructors to be accessed by static
methods on the class.

Bug: 1058320
Change-Id: I04afc8caf64acf29cdda13ef03ad05cfff4786a1
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2091450
Commit-Queue: Paul Lewis <[email protected]>
Reviewed-by: Tim van der Lippe <[email protected]>
diff --git a/front_end/console/ConsoleSidebar.js b/front_end/console/ConsoleSidebar.js
index 0ab6bfc..b5583c6 100644
--- a/front_end/console/ConsoleSidebar.js
+++ b/front_end/console/ConsoleSidebar.js
@@ -24,7 +24,8 @@
     this._selectedTreeElement = null;
     /** @type {!Array<!FilterTreeElement>} */
     this._treeElements = [];
-    const selectedFilterSetting = self.Common.settings.createSetting('console.sidebarSelectedFilter', null);
+    const selectedFilterSetting =
+        Common.Settings.Settings.instance().createSetting('console.sidebarSelectedFilter', null);
 
     const Levels = SDK.ConsoleModel.MessageLevel;
     const consoleAPIParsedFilters =