Make GlobalErrorService's ownership model slightly less insane.

GlobalErrorService ownership was crazy; sometimes the error objects contained were owned, and sometimes they weren't. This separates the two cases into clear statements of ownership, and deprecates the case where the error objects are unowned.

BUG=555865,673578

Review-Url: https://codereview.chromium.org/2409443002
Cr-Commit-Position: refs/heads/master@{#438192}
13 files changed