linux_aura: Fix ASAN bug in the app indicator handling code.

BUG=310834

Review URL: https://codereview.chromium.org/42503002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230953 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 230953