rebaseline.py: make builder names copy-pastable from --help output
BUG=skia:1653
(SkipBuildbotRuns)

R=bsalomon@google.com

Review URL: https://codereview.chromium.org/23514068

git-svn-id: http://skia.googlecode.com/svn/trunk@11347 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tools/rebaseline.py b/tools/rebaseline.py
index 19d705b..502bcc9 100755
--- a/tools/rebaseline.py
+++ b/tools/rebaseline.py
@@ -329,7 +329,10 @@
 
 # main...
 
-parser = argparse.ArgumentParser()
+parser = argparse.ArgumentParser(
+    formatter_class=argparse.RawDescriptionHelpFormatter,
+    epilog='Here is the full set of builders we know about:' +
+           '\n    '.join([''] + sorted(TEST_BUILDERS)))
 parser.add_argument('--actuals-base-url',
                     help=('base URL from which to read files containing JSON '
                           'summaries of actual GM results; defaults to '
@@ -351,8 +354,8 @@
                           'pertain to this set of rebaselines.'))
 parser.add_argument('--builders', metavar='BUILDER', nargs='+',
                     help=('which platforms to rebaseline; '
-                          'if unspecified, rebaseline all platforms, same as '
-                          '"--builders %s"' % ' '.join(sorted(TEST_BUILDERS))))
+                          'if unspecified, rebaseline all known platforms '
+                          '(see below for a list)'))
 # TODO(epoger): Add test that exercises --configs argument.
 parser.add_argument('--configs', metavar='CONFIG', nargs='+',
                     help=('which configurations to rebaseline, e.g. '