Revert "isolated_app: Do not allow access to the gpu_device."

Chrome team recommends reverting this patch and introducing
it into a future version of Android, to avoid potential
compatibility issues.

This reverts commit 9de62d6f.

Bug: 17471434
Bug: 18609318
Change-Id: I9adaa9d0e4cb6a592011336e442e9d414dbac470