Reduce WebContents usage in PermissionManager and PermissionContextBase.

PermissionManager was migrated to a new API that relies on RenderFrameHost. This CL reduces usage of WebContent and most importantly moves content::WebContents::FromRenderFrameHost(rfh) from  PermissionManager into PermissionContextBase after MPArch related verifications.

This CL removes WebContents from:
1. PermissionContextBase::RequestPermission
2. PermissionContextBase::DecidePermission

Bug: 1227711
Change-Id: I40c938bcd99c364bb5fed03e9dac28c5e49c8f82
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3660485
Reviewed-by: Rayan Kanso <rayankans@chromium.org>
Reviewed-by: Robbie McElrath <rmcelrath@chromium.org>
Reviewed-by: Ravjit Uppal <ravjit@chromium.org>
Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Commit-Queue: Illia Klimov <elklm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1008242}