Revert "Encapsulate WebScopedVirtualTimePauser inside Blink"

This reverts commit 3d4ab06a4fded7fd29b5e5eac3df16dcda20aabe.

Reason for revert: broke history navigation with virtual time.

Original change's description:
> Encapsulate WebScopedVirtualTimePauser inside Blink
> 
> This moves history navigation virtual time pauser from
> RenderViewImpl to Page, which has two benefits:
> - slimming down RenderViewImpl;
> - encapsulating virtual time inside Blink.
> 
> Most of changes are moving virtual time pauser creation
> from thread scheduler to page scheduler.
> 
> Bug: none
> Change-Id: I9fc2683e974e005d8cea35ced0f5f82931215b5a
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1856929
> Reviewed-by: Alex Clarke <[email protected]>
> Reviewed-by: Alexander Timin <[email protected]>
> Commit-Queue: Dmitry Gozman <[email protected]>
> Cr-Commit-Position: refs/heads/master@{#705679}

[email protected],[email protected],[email protected],[email protected]

Change-Id: Ib2ebc3ebb4710201969a24e8d63f1f022df7fa9e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: none
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1862249
Reviewed-by: Andrey Kosyakov <[email protected]>
Commit-Queue: Andrey Kosyakov <[email protected]>
Cr-Commit-Position: refs/heads/master@{#706020}
20 files changed