Remove log filtering and add stringsetflag.

common/logging/config.go

 // 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"
 
         "golang.org/x/net/context"
 )
 
 // Config is a logging configuration structure.
 type Config struct {
-        Level  Level
-        Filter Filter
+        Level Level
 }
 
 // AddFlags adds common flags to a supplied FlagSet.
 func (c *Config) AddFlags(fs *flag.FlagSet) {
-        fs.Var(&c.Level, "log_level",
+        fs.Var(&c.Level, "log-level",
                 "The logging level. Valid options are: debug, info, warning, error.")
-        fs.Var(&c.Filter, "log_filter",
-                "Log filter keywords. Can be specified multiple times.")
 }
 
-// Set installs a filter-aware logger that wraps the currently-installed Logger
-// and selectively discards messages based on the logging configuration.
+// Set installs a logger that wraps the currently-installed Logger and sets
+// the level via the command-line level flag.
 func (c *Config) Set(ctx context.Context) context.Context {
-        filterFunc := c.Filter.Get()
-        baseFactory := GetFactory(ctx)
-
-        ctx = SetLevel(ctx, c.Level)
-        return SetFactory(ctx, func(ctx context.Context) Logger {
-                if value, ok := GetFields(ctx)[FilterOnKey]; ok {
-                        if !filterFunc(value) {
-                                return Null()
-                        }
-                }
-                return baseFactory(ctx)
-        })
+        return SetLevel(ctx, c.Level)
 }