Remove third_party/golang.org/x/mobile as it is no longer used with Go 1.5.

third_party/go/src/golang.org/x/mobile/cmd/gobind/main.go

-// Copyright 2014 The Go 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 (
-        "flag"
-        "fmt"
-        "go/build"
-        "log"
-        "os"
-)
-
-var (
-        lang   = flag.String("lang", "java", "target language for bindings, either java or go.")
-        outdir = flag.String("outdir", "", "result will be written to the directory instead of stdout.")
-)
-
-var usage = `The Gobind tool generates Java language bindings for Go.
-
-For usage details, see doc.go.`
-
-func main() {
-        flag.Parse()
-
-        cwd, err := os.Getwd()
-        if err != nil {
-                log.Fatal(err)
-        }
-        for _, arg := range flag.Args() {
-                pkg, err := build.Import(arg, cwd, 0)
-                if err != nil {
-                        fmt.Fprintf(os.Stderr, "%s: %v\n", arg, err)
-                        os.Exit(1)
-                }
-                genPkg(pkg)
-        }
-        os.Exit(exitStatus)
-}
-
-var exitStatus = 0
-
-func errorf(format string, args ...interface{}) {
-        fmt.Fprintf(os.Stderr, format, args...)
-        fmt.Fprintln(os.Stderr)
-        exitStatus = 1
-}