src/vs/workbench/services/themes/browser/workbenchThemeService.ts/ThemeFileWatcher/update
class ThemeFileWatcher:	update(theme: { location?: URI; watch?: boolean }) {
		if (!resources.isEqual(theme.location, this.watchedLocation)) {
			this.dispose();
			if (theme.location && (theme.watch || this.environmentService.isExtensionDevelopment)) {
				this.watchedLocation = theme.location;
				this.watcherDisposable = this.fileService.watch(theme.location);
				this.fileService.onDidFilesChange(e => {
					if (this.watchedLocation && e.contains(this.watchedLocation, FileChangeType.UPDATED)) {
						this.onUpdate();
					}
				});
			}
		}
	}