Add archive/zip from go1.7rc5 tag

In preparation to patch in some custom functionality (parallel
compression and zero-decompress zip to zip copying)

Change-Id: I96a36efc09c715f6b55290af40ebfdde9ae72e33

third_party/zip/example_test.go

@@ -0,0 +1,93 @@
+// Copyright 2012 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 zip_test
+
+import (
+	"archive/zip"
+	"bytes"
+	"compress/flate"
+	"fmt"
+	"io"
+	"log"
+	"os"
+)
+
+func ExampleWriter() {
+	// Create a buffer to write our archive to.
+	buf := new(bytes.Buffer)
+
+	// Create a new zip archive.
+	w := zip.NewWriter(buf)
+
+	// Add some files to the archive.
+	var files = []struct {
+		Name, Body string
+	}{
+		{"readme.txt", "This archive contains some text files."},
+		{"gopher.txt", "Gopher names:\nGeorge\nGeoffrey\nGonzo"},
+		{"todo.txt", "Get animal handling licence.\nWrite more examples."},
+	}
+	for _, file := range files {
+		f, err := w.Create(file.Name)
+		if err != nil {
+			log.Fatal(err)
+		}
+		_, err = f.Write([]byte(file.Body))
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+
+	// Make sure to check the error on Close.
+	err := w.Close()
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+func ExampleReader() {
+	// Open a zip archive for reading.
+	r, err := zip.OpenReader("testdata/readme.zip")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer r.Close()
+
+	// Iterate through the files in the archive,
+	// printing some of their contents.
+	for _, f := range r.File {
+		fmt.Printf("Contents of %s:\n", f.Name)
+		rc, err := f.Open()
+		if err != nil {
+			log.Fatal(err)
+		}
+		_, err = io.CopyN(os.Stdout, rc, 68)
+		if err != nil {
+			log.Fatal(err)
+		}
+		rc.Close()
+		fmt.Println()
+	}
+	// Output:
+	// Contents of README:
+	// This is the source code repository for the Go programming language.
+}
+
+func ExampleWriter_RegisterCompressor() {
+	// Override the default Deflate compressor with a higher compression level.
+
+	// Create a buffer to write our archive to.
+	buf := new(bytes.Buffer)
+
+	// Create a new zip archive.
+	w := zip.NewWriter(buf)
+
+	// Register a custom Deflate compressor.
+	w.RegisterCompressor(zip.Deflate, func(out io.Writer) (io.WriteCloser, error) {
+		return flate.NewWriter(out, flate.BestCompression)
+	})
+
+	// Proceed to add files to w.
+}