Add in basic logging system.

utils/pub/command_help.dart

Index: utils/pub/command_help.dart
diff --git a/utils/pub/command_help.dart b/utils/pub/command_help.dart
index 7681f3744f2f7fddb3dcbfedcf1ad469912621aa..1484b7b06d4ecd84dbd1737bea060320accda710 100644
--- a/utils/pub/command_help.dart
+++ b/utils/pub/command_help.dart
@@ -7,6 +7,7 @@ library command_help;
 import 'dart:io' as io;
 import 'exit_codes.dart' as exit_codes;
 import 'io.dart';
+import 'log.dart' as log;
 import 'pub.dart';
 
 /** Handles the `help` pub command. */
@@ -22,8 +23,8 @@ class HelpCommand extends PubCommand {
       var name = commandOptions.rest[0];
       var command = pubCommands[name];
       if (command == null) {
-        printError('Could not find a command named "$name".');
-        printError('Run "pub help" to see available commands.');
+        log.error('Could not find a command named "$name".');
+        log.error('Run "pub help" to see available commands.');
         io.exit(exit_codes.USAGE);
       }