Remove log filtering and add stringsetflag.

common/flag/stringsetflag/stringsetflag_test.go

Index: common/flag/stringsetflag/stringsetflag_test.go
diff --git a/common/flag/stringsetflag/stringsetflag_test.go b/common/flag/stringsetflag/stringsetflag_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..2ba62cfca813eed44bee6c781fd0e89e18103e38
--- /dev/null
+++ b/common/flag/stringsetflag/stringsetflag_test.go
@@ -0,0 +1,36 @@
+// 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
+}