tree b5221be7ee35e1b7e2cfed8f931a704cc5f40da4
parent 335675c2fd8ff39e5af635eb375edc766147cbb9
author Christopher Ferris <cferris@google.com> 1516758743 -0800
committer Christopher Ferris <cferris@google.com> 1516845046 -0800

Add error propagation into Unwinder/Elf objects.

The backtrace offline code uses these error codes to diagnose errors.
In addtion, I've had cases where seeing these errors would help diagnose
failures.

This also allows us to add a few features to indicate why an unwind
terminated (such as max frames exceeded).

Bug: 65682279

Test: Updated unit tests pass.
Change-Id: If82b5092698e8a194016d670efff1320f9b44d50