[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/network/RequestHeadersView.js b/front_end/network/RequestHeadersView.js
index 72d3060..5ccadf7 100644
--- a/front_end/network/RequestHeadersView.js
+++ b/front_end/network/RequestHeadersView.js
@@ -872,7 +872,8 @@
     super(title || '', true);
     this.toggleOnClick = true;
     this.hidden = true;
-    this._expandedSetting = self.Common.settings.createSetting('request-info-' + name + '-category-expanded', true);
+    this._expandedSetting =
+        Common.Settings.Settings.instance().createSetting('request-info-' + name + '-category-expanded', true);
     this.expanded = this._expandedSetting.get();
     root.appendChild(this);
   }