src/vs/workbench/browser/parts/editor/tabsTitleControl.ts/TabsTitleControl/getHeight
class TabsTitleControl:	getHeight(): IEditorGroupTitleHeight {
		const showsBreadcrumbs = this.breadcrumbsControl && !this.breadcrumbsControl.isHidden();

		// Return quickly if our used dimensions are known
		if (this.dimensions.used) {
			return {
				total: this.dimensions.used.height,
				offset: showsBreadcrumbs ? this.dimensions.used.height - BreadcrumbsControl.HEIGHT : this.dimensions.used.height
			};
		}

		// Otherwise compute via browser APIs
		else {
			return this.computeHeight();
		}
	}