Basic shell class for Image

Bug b/119620767

Change-Id: I75d37dd8c1a9b98264fe6dae68cd4753d6942103
Reviewed-on: https://swiftshader-review.googlesource.com/c/22610Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>