Synchronously sample font styling when global editor stylesheet changes

And don’t sample font styling in pollDOM, which we are aiming to
eliminate.

Signed-off-by: Max Brunsfeld <maxbrunsfeld@github.com>

src/workspace-element.js

@@ -64,7 +64,6 @@ class WorkspaceElement extends HTMLElement {
   line-height: ${this.config.get('editor.lineHeight')};
 }`
     this.styleManager.addStyleSheet(styleSheetSource, {sourcePath: 'global-text-editor-styles', priority: -1})
-    this.viewRegistry.performDocumentPoll()
   }
 
   initialize (model, {config, project, styleManager, viewRegistry}) {