Revert "Avoid throwing ISE in Canvas#restore underflow"

Additionally, rewrite the exception message for clarity.

bug:19951475
bug:19829784

This reverts commit 14cfb6db33264f1c3b127ccf4e45e3ac86527804.

Change-Id: Ie70a49a8d3957025c4b2e47d4ef9f4abd4ded133
1 file changed