Add --no-history option to fetch and gclient for shallow clones.

gclient_utils.py

Index: gclient_utils.py
diff --git a/gclient_utils.py b/gclient_utils.py
index 9c62a2a5b53af41b5aedae595bda06ecc61b1b77..7cea99511f0b59e750dee15c7c77d5b26c40404d 100644
--- a/gclient_utils.py
+++ b/gclient_utils.py
@@ -88,6 +88,9 @@ def IsDateRevision(revision):
   """Returns true if the given revision is of the form "{ ... }"."""
   return bool(revision and re.match(r'^\{.+\}$', str(revision)))
 
+def IsGitSha(text):

[wtc, 2014/08/03 04:12:49]

Nit: I know you listed IsGitSha after another IsXXX function, but it is now
between two functions related to DateRevision. Perhaps we should list IsGitSha
before IsDateRevision?

[Primiano Tucci (use gerrit), 2014/08/03 17:43:34]

Oh right, didn't realize that. Done.

+  """Returns true if the given string is a valid hex-encoded sha"""
+  return re.match('^[a-fA-F0-9]{6,40}$', text) != None
 
 def MakeDateRevision(date):
   """Returns a revision representing the latest revision before the given