src/vs/workbench/services/keybinding/browser/keybindingService.ts/WorkbenchKeybindingService/_documentHasFocus
class WorkbenchKeybindingService:	protected _documentHasFocus(): boolean {
		// it is possible that the document has lost focus, but the
		// window is still focused, e.g. when a <webview> element
		// has focus
		return this.hostService.hasFocus;
	}