Add AwResource.java, a class that defines a set of resource IDs and
functionality to resolve those IDs to concrete resources.
Initially, we add three resources - two raw resources to represent
error pags and a string resource for default text encoding.
The embedder should set up the IDs before starting to use Chromium.
Review URL: https://codereview.chromium.org/11145026
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@162205 0039d316-1c4b-4281-b951-d872f2087c98