Revert "Use webview provider for shell layout and ui webview tests."

This reverts commit 37511ad65414d7d7fd43d4620bc2f7fb91e8b2be.

Reason for revert: seems to be causing gn gen failures.

Original change's description:
> Use webview provider for shell layout and ui webview tests.
> 
> This prepares the way to switch webview test bots to use swarmed devices.
> 
> Bug: 814405
> Change-Id: Ic6c1f2b713392b3ed80b26dae1a5571de648914d
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1526809
> Reviewed-by: Ben Pastene <bpastene@chromium.org>
> Reviewed-by: Richard Coles <torne@chromium.org>
> Commit-Queue: Andrew Luo <aluo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#642127}

TBR=torne@chromium.org,bpastene@chromium.org,aluo@chromium.org

Change-Id: Ic483c70cd0d77b4bee33784c9c3900a339ccb579
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 814405
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1531233
Reviewed-by: Ian Vollick <vollick@chromium.org>
Commit-Queue: Ian Vollick <vollick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#642154}
2 files changed