message: convert operations
diff: @@ -78,6 +78,16 @@ function convertInterfaceCommon(i: webidl2.InterfaceType | webidl2.InterfaceMixi
  else if (member.type === "attribute") {
  result.properties!.property[member.name] = convertAttribute(member);
  }
  + else if (member.type === "operation" && member.name) {
  + const operation = convertOperation(member);
  + const { method } = result.methods;
  + if (method[member.name]) {
  + method[member.name].signature.push(...operation.signature);
  + }
  + else {
  + method[member.name] = operation;
  + }
  + }
  }
  return result;
  @@ -100,18 +110,17 @@ function getConstructor(extAttrs: webidl2.ExtendedAttributes[], parent: string)
  }
  }
  -function convertOperation(operation: webidl2.OperationMemberType) {
  - const result: Browser.Method = {
  +function convertOperation(operation: webidl2.OperationMemberType): Browser.Method {
  + return {
  name: operation.name!,
  - signature: [],
  + signature: [{
  + ...convertIdlType(operation.idlType!),
  + param: operation.arguments.map(convertArgument)
  + }],
  getter: operation.getter ? 1 : undefined,
  static: operation.static ? 1 : undefined,
  stringifier: operation.stringifier ? 1 : undefined,
  - }
  -
  - operation.arguments
  -
  - return result;
  + };
  }
  function convertCallbackFunctions(c: webidl2.CallbackType): Browser.CallbackFunction {
  