Add third_party/undoview to .gitignore

This directory is now pulled in via DEPS.

BUG=111334


Review URL: http://codereview.chromium.org/9316030

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@120060 0039d316-1c4b-4281-b951-d872f2087c98

.gitignore

@@ -151,6 +151,7 @@ v8.log
 /third_party/speex
 /third_party/swig
 /third_party/syzygy/binaries
+/third_party/undoview
 /third_party/v8-i18n
 /third_party/valgrind
 /third_party/webdriver/pylib