Revert "Renaming and refactoring to prepare for init-once threaded backend"

This reverts commit 07a42411f8d4a00d992bafdd18f2183f58c4547a.

Reason for revert: This looks to be breaking the Android roll. See https://googleplex-android-review.googlesource.com/c/platform/external/skia/+/3295488

external/skia/src/core/SkTaskGroup2D.cpp:73:28: error: releasing mutex 'rowData.fMutex' that was not held [-Werror,-Wthread-safety-analysis]
            rowData.fMutex.unlock();


Original change's description:
> Renaming and refactoring to prepare for init-once threaded backend
> 
> Bug: skia:
> Change-Id: I39b1d73b612a9c133847dd7361d634a0351659f1
> Reviewed-on: https://skia-review.googlesource.com/70221
> Reviewed-by: Herb Derby <herb@google.com>
> Commit-Queue: Yuqian Li <liyuqian@google.com>

TBR=mtklein@google.com,herb@google.com,liyuqian@google.com

Change-Id: I701e6c62f6f437a6a285953b45b2e58cf7f0b6e5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/78720
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
5 files changed