Replace ErrorExit with log.Fatal in the mojom tool.

mojom/mojom_parser/mojom_main.go

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package main
 
 import (
         "bytes"
         "flag"
         "fmt"
+        "log"
         "os"
 )
 
 // This file contains the main() for the mojom tool binary.
 // The mojom tool is used to process .mojom files.
 //
 // The tool is invoked as follows:
 //
 //              mojom <command> [<arguments>]
 //
 //      where <commands> is one of:
 //              - parse
 //              - fmt
 //
 //      For further information about each command, see the file named
 //      <command>_cmd.go for example "parse_cmd.go" and "fmt_cmd.go".
 func main() {
+        log.SetFlags(0)
         checkVersion(os.Args)
         commands := NewCommandSet()
         commands.AddCommand("parse", parseCmd, "Parses mojom files.")
         commands.AddCommand("fmt", fmtCmd, "Formats a mojom file.")
         commands.AddHelpCommand()
         commands.RunCommand(os.Args)
 }
 
-func ErrorExit(message string) {
-        fmt.Fprintf(os.Stderr, "%s\n", message)
-        os.Exit(1)
-}
-
 type command struct {
         Name string
         Func func([]string)
         Desc string
 }
 
 type commandSet struct {
         commandNames []string
         commandMap   map[string]command
 }
@@ skipping 77 matching lines @@
                 s += "\n    \t"
                 s += f.Usage
                 if !isZeroValue(f.DefValue) {
                         s += fmt.Sprintf(" (default %q)", f.DefValue)
                 }
                 b.WriteString(fmt.Sprint(s, "\n"))
         })
 
         return b.String()
 }