Ensure files passed to the editor by RunEditor end in a new line

BUG=605201

Review URL: https://codereview.chromium.org/1905693002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@300049 0039d316-1c4b-4281-b951-d872f2087c98

gclient_utils.py

@@ -1084,7 +1084,11 @@ def RunEditor(content, git, git_editor=None):
         '!! Please remove \\r from your change description !!')
   fileobj = os.fdopen(file_handle, 'w')
   # Still remove \r if present.
-  fileobj.write(re.sub('\r?\n', '\n', content))
+  content = re.sub('\r?\n', '\n', content)
+  # Some editors complain when the file doesn't end in \n.
+  if not content.endswith('\n'):
+    content += '\n'
+  fileobj.write(content)
   fileobj.close()
 
   try: