Remove log filtering and add stringsetflag.

common/logging/filter.go

Index: common/logging/filter.go
diff --git a/common/logging/filter.go b/common/logging/filter.go
deleted file mode 100644
index 41406efd46b31df59166144ea09ebb647f5c1f06..0000000000000000000000000000000000000000
--- a/common/logging/filter.go
+++ /dev/null
@@ -1,66 +0,0 @@
-// Copyright 2015 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 logging
-
-import (
-	"flag"
-	"strings"
-)
-
-const (
-	// FilterOnAll is a Filter value that, when included in a Filter, causes it to
-	// display all log messages.
-	FilterOnAll = "all"
-
-	// FilterOnKey is a log field key whose value specifies the context's filter.
-	FilterOnKey = "_filterOn"
-)
-
-// Filter is a configurable list of strings to filter on, when the 'filterOn'
-// property is supplied.
-type Filter []string
-
-var _ flag.Value = (*Filter)(nil)
-
-// Set implements flag.Value.
-func (f *Filter) Set(v string) error {
-	if len(v) > 0 {
-		*f = append(*f, v)
-	}
-	return nil
-}
-
-// String implements flag.Value.
-func (f *Filter) String() string {
-	return strings.Join([]string(*f), ",")
-}
-
-// Get returns a filter function that returns true if the Filter passes the
-// supplied log flags.
-func (f Filter) Get() func(interface{}) bool {
-	filterMap := make(map[string]bool)
-	for _, filter := range f {
-		if filter == FilterOnAll {
-			filterMap = nil
-			break
-		}
-		filterMap[filter] = true
-	}
-
-	return func(filterOn interface{}) bool {
-		if filterMap == nil || filterOn == nil {
-			return true
-		}
-
-		switch t := filterOn.(type) {
-		case string:
-			_, ok := filterMap[t]
-			return ok
-
-		default:
-			return true
-		}
-	}
-}