Support serving from multiple directories using "pub serve".

sdk/lib/_internal/pub/lib/src/log.dart

Index: sdk/lib/_internal/pub/lib/src/log.dart
diff --git a/sdk/lib/_internal/pub/lib/src/log.dart b/sdk/lib/_internal/pub/lib/src/log.dart
index 0dcf088d339cfbb43c1ce0d2275cab8b57d9d81c..fd1166d99644e29795f0301e41fbcf2c3e532e8b 100644
--- a/sdk/lib/_internal/pub/lib/src/log.dart
+++ b/sdk/lib/_internal/pub/lib/src/log.dart
@@ -41,6 +41,7 @@ final _green = getSpecial('\u001b[32m');
 final _magenta = getSpecial('\u001b[35m');
 final _red = getSpecial('\u001b[31m');
 final _yellow = getSpecial('\u001b[33m');
+final _gray = getSpecial('\u001b[1;30m');
 final _none = getSpecial('\u001b[0m');
 final _bold = getSpecial('\u001b[1m');
 
@@ -237,6 +238,12 @@ Future progress(String message, Future callback()) {
 /// Use this to highlight the most important piece of a long chunk of text.
 String bold(text) => "$_bold$text$_none";
 
+/// Wraps [text] in the ANSI escape codes to make it gray when on a platform
+/// that supports that.
+///
+/// Use this for text that's less important than the text around it.
+String gray(text) => "$_gray$text$_none";
+
 /// Wraps [text] in the ANSI escape codes to color it cyan when on a platform
 /// that supports that.
 ///