Revert of Change SkResourceCache to take a Visitor inside its find(). (patchset #2 id:20001 of https://codereview.chromium.org/567393002/)

Reason for revert:
crashes on android bots, haven't diagnosed yet

Original issue's description:
> Change SkResourceCache to take a Visitor inside its find().
>
> This simplifies the API/contract, in that there are not any exposed
> lock/unlock scopes.
>
>
> patch from issue 572573002
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/dee6a8e67db39fcbde2b3bb09be1d088ebb9db8a

R=mtklein@google.com, danakj@chromium.org
TBR=danakj@chromium.org, mtklein@google.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Author: reed@google.com

Review URL: https://codereview.chromium.org/569303002
5 files changed