Increase targetSdkVersion to 19.

BUG=317754
NOTRY=true
TBR=abarth@chromium.org

Review URL: https://codereview.chromium.org/68203025

git-svn-id: http://src.chromium.org/chrome/trunk/src/testing@236540 4ff67af0-8c30-449e-8e8b-ad334ec8d88c