chromeos: Update libcros dep to 7537f1e8.
chromeos: Update libcros dep to 7537f1e8.

TEST=built and ran chrome; checked that it was interacting with libcros
BUG=chromium-os:4816

Review URL: http://codereview.chromium.org/5603012

git-svn-id: http://src.chromium.org/svn/trunk/src@68661 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: d8b0a3f3300003c6dbff9b61c11f6618d8ce480a
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser