isolate client: get back faster compression library.

common/isolated/algo.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 // Defines the algorithms used by the isolated server.
 
 package isolated
 
 import (
-        "compress/zlib"
         "crypto/sha1"
         "hash"
         "io"
         "log"
-        // https://crbug.com/552697
-        //"github.com/klauspost/compress/zlib"
+
+        // TODO(tandrii): this library became part of Go 1.7, So, switch back to
+        // standard library compress/zlib once we are solidly on Go > 1.7
+        "github.com/klauspost/compress/zlib"
 )
 
 var hashLength = sha1.New().Size()
 
 // GetHash returns a fresh instance of the hashing algorithm to be used to
 // calculate the HexDigest.
 //
 // It is currently hardcoded to sha-1.
 func GetHash() hash.Hash {
         return sha1.New()
@@ skipping 40 matching lines @@
         }
         return true
 }
 
 // HexDigests is a slice of HexDigest that implements sort.Interface.
 type HexDigests []HexDigest
 
 func (h HexDigests) Len() int           { return len(h) }
 func (h HexDigests) Less(i, j int) bool { return h[i] < h[j] }
 func (h HexDigests) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }