Use "git log" instead of "git svn info" for revision number information, since

tools/utils.py

Index: tools/utils.py
diff --git a/tools/utils.py b/tools/utils.py
index f4a37553c5ede21e3f24afe4e684b5ab465dea25..fc55a5b1cfd7dc8789f10310cc97e80807bf35e0 100644
--- a/tools/utils.py
+++ b/tools/utils.py
@@ -366,11 +366,13 @@ def GetSVNRevision():
   if revision:
     return revision
 
-  # maybe the builder is using git-svn, try that
-  p = subprocess.Popen(['git', 'svn', 'info'], stdout = subprocess.PIPE,
+  # Check for revision using git (Note: we can't use git-svn because in a
+  # pure-git checkout, "git-svn anyCommand" just hangs!). We look an arbitrary
+  # number of commits backwards (100) to get past any local commits.

[ricow1, 2014/06/10 10:44:10]

will this actually give the correct revision?

[Emily Fortuna, 2014/06/10 16:08:47]

Yup, as long as there are no more than 100 local commits

+  p = subprocess.Popen(['git', 'log', '-100'], stdout = subprocess.PIPE,
       stderr = subprocess.STDOUT, shell=IsWindows(), cwd = DART_DIR)

[Emily Fortuna, 2014/06/09 17:45:41]

Yeah, the 100 is gross, but better than hanging indefinitely. I'm happy to
consider other suggestions.

   output, _ = p.communicate()
-  revision = ParseSvnInfoOutput(output)
+  revision = ParseGitInfoOutput(output)
   if revision:

[blois, 2014/06/16 19:20:12]

Could fall back to git svn info if this fails, just to be safe.

     return revision
 
@@ -381,6 +383,14 @@ def GetSVNRevision():
 
   return None
 
+def ParseGitInfoOutput(output):
+  """Given a git log, determine the latest corresponding svn revision."""
+  for line in output.split('\n'):
+    tokens = line.split()
+    if len(tokens) > 0 and tokens[0] == 'git-svn-id:':
+      return tokens[1].split('@')[1]
+  return None
+
 def ParseSvnInfoOutput(output):
   revision_match = re.search('Last Changed Rev: (\d+)', output)
   if revision_match: