Add API for glyph cache read failures

This will allow chromium to do a dump without crashing so we can get
more information about what's going wrong on webview in the field.

Bug: chromium:977231
Change-Id: I9022921aded735764d36868bb6606674654439bc
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/228389
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Khushal Sagar <khushalsagar@chromium.org>
Commit-Queue: Mike Klein <mtklein@google.com>
Auto-Submit: Adrienne Walker <enne@chromium.org>
2 files changed