Fixes the naming in the About page of CrOS.
Introduces a new constant IDS_SHORT_PRODUCT_OS_NAME (i.e., Chrome OS), and changes the old constant IDS_PRODUCT_OS_NAME to be the full name (i.e., Google Chrome OS) to remain in sync with the other string names. Changes previous references to IDS_PRODUCT_OS_NAME to IDS_SHORT_PRODUCT_OS_NAME.
BUG=122645
TEST=look at help page on CrOS and see that text says Google Chrome OS
Review URL: https://chromiumcodereview.appspot.com/
10388120
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@137195 0039d316-1c4b-4281-b951-d872f2087c98