[android_webview] Add angle to deps_whitelist.

This is a prerequisite for getting http://crrev.com/106623003
through the AOSP trybot.

BUG=319527
R=torne@chromium.org

Review URL: https://codereview.chromium.org/111343004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@240110 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 240110