Remove unused variable declarations.

This issue was found by a linter.

R=mpearson@chromium.org
BUG=

Review URL: https://codereview.chromium.org/23578014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225640 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225640