bind/java: fix build

Tested on darwin/amd64 with
	go build golang.org/x/mobile/...

Change-Id: Iec31ccb318913cea5acc7dcec1c6a858bf8654de
Reviewed-on: https://go-review.googlesource.com/5770
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

bind/java/doc.go

@@ -1,6 +1,16 @@
+// Copyright 2015 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 java implements the Java language bindings.
 //
 // See the design document (http://golang.org/s/gobind).
 //
 // Currently, this works only for android.
 package java
+
+// Init initializes communication with Java.
+// Typically called from the Start callback in app.Run.
+func Init() {
+	initSeq()
+}

bind/java/noimpl.go

@@ -0,0 +1,9 @@
+// Copyright 2015 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.
+
+// +build !android
+
+package java
+
+func initSeq() {}

bind/java/seq_android.go

@@ -78,9 +78,7 @@ func init() {
 	res.out = make(map[int32]*seq.Buffer)
 }
 
-// Init initializes communication with Java.
-// Typically called from the Start callback in app.Run.
-func Init() {
+func initSeq() {
 	vm := app.State.(interface {
 		JavaVM() unsafe.Pointer
 	}).JavaVM()