Restore previous behavior of GetSha1ForSvnRev, so unit tests pass.

scm.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """SCM-specific utility classes."""
 
 import cStringIO
 import glob
 import logging
 import os
@@ skipping 384 matching lines @@
     """Parses git-svn output for the first sha1."""
     match = re.search(r'[0-9a-fA-F]{40}', output)
     return match.group(0) if match else None
 
   @staticmethod
   def GetSha1ForSvnRev(cwd, rev):
     """Returns a corresponding git sha1 for a SVN revision."""
     if not GIT.IsGitSvn(cwd=cwd):
       return None
     try:
-      git_svn_rev = GIT.Capture(
-          ['svn', 'find-rev', 'r' + str(rev)], cwd=cwd).rstrip()
-      if not git_svn_rev:
-        return None
+      output = GIT.Capture(['svn', 'find-rev', 'r' + str(rev)], cwd=cwd)
+      return GIT.ParseGitSvnSha1(output)
+    except subprocess2.CalledProcessError:
+      return None
+
+  @staticmethod
+  def GetBlessedSha1ForSvnRev(cwd, rev):
+    """Returns a git commit hash from the master branch history that has
+    accurate .DEPS.git and git submodules.  To understand why this is more
+    complicated than a simple call to `git svn find-rev`, refer to:
+
+    http://www.chromium.org/developers/how-tos/git-repo
+    """
+    git_svn_rev = GIT.GetSha1ForSvnRev(cwd, rev)
+    if not git_svn_rev:
+      return None
+    try:
       output = GIT.Capture(
           ['rev-list', '--ancestry-path', '--reverse',
           '--grep', 'SVN changes up to revision [0-9]*',
           '%s..refs/remotes/origin/master' % git_svn_rev], cwd=cwd)
       if not output:
         return None
       sha1 = output.splitlines()[0]
       if not sha1:
         return None
       output = GIT.Capture(['rev-list', '-n', '1', '%s^1' % sha1], cwd=cwd)
@@ skipping 664 matching lines @@
         # revert, like for properties.
         if not os.path.isdir(cwd):
           # '.' was deleted. It's not worth continuing.
           return
         try:
           SVN.Capture(['revert', file_status[1]], cwd=cwd)
         except subprocess2.CalledProcessError:
           if not os.path.exists(file_path):
             continue
           raise