Remove support for product attributes in Android xml files.

The product attribute was never used, except in one place in Chrome that
wasn't actually needed (see
Further, the product attribute has no compelling use case in typical
development and isn't even documented on (See:

This also updates the header comment in to explain the
new <plurals> feature added in

Review URL: .

git-svn-id: 7262f16d-afe8-6277-6482-052fa10e57b1
5 files changed