Remove log filtering and add stringsetflag.

common/flag/stringsetflag/stringsetflag_test.go

+// Copyright 2016 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 stringsetflag
+
+import (
+        "flag"
+        "fmt"
+        "os"
+)
+
+// Example demonstrates how to use flagenum to create bindings for a custom
+// type.
+func Example() {
+        sset := Flag{}
+
+        fs := flag.NewFlagSet("test", flag.ContinueOnError)
+        fs.Var(&sset, "color", "favorite color, may be repeated.")
+        fs.SetOutput(os.Stdout)
+
+        fs.PrintDefaults()
+
+        // Flag parsing.
+        fs.Parse([]string{"-color", "Violet", "-color", "Red", "-color", "Violet"})
+        fmt.Printf("Value is: %s\n", sset)
+
+        fmt.Println("Likes Blue:", sset.Data.Has("Blue"))
+        fmt.Println("Likes Red:", sset.Data.Has("Red"))
+
+        // Output:
+        // -color=: favorite color, may be repeated.
+        // Value is: Red,Violet
+        // Likes Blue: false
+        // Likes Red: true
+}