src/vs/workbench/api/common/extHostSCM.ts/ExtHostSourceControl/constructor
class ExtHostSourceControl:	constructor(
		_extension: IExtensionDescription,
		private _proxy: MainThreadSCMShape,
		private _commands: ExtHostCommands,
		private _id: string,
		private _label: string,
		private _rootUri?: vscode.Uri
	) {
		this._inputBox = new ExtHostSCMInputBox(_extension, this._proxy, this.handle);
		this._proxy.$registerSourceControl(this.handle, _id, _label, _rootUri);
	}