Revert "Reland "Trigger heavy ad intervention when an unloaded heavy ad navigates""

This reverts commit 0c891022.

Reason for revert: https://bugs.chromium.org/p/chromium/issues/detail?id=1109599#c10

Original change's description:
> Reland "Trigger heavy ad intervention when an unloaded heavy ad navigates"
>
> This is a reland of 312a57a1
>
> Original change's description:
> > Trigger heavy ad intervention when an unloaded heavy ad navigates
> >
> > Bug: 1099014
> > Change-Id: I98a2d0e548a48fd93618fbae1c1d458f1dbd58a4
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2269740


> > Reviewed-by: John Delaney <johnidel@chromium.org>
> > Commit-Queue: Andrew Paseltiner <apaseltiner@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#791488}
>
> Bug: 1099014
> Change-Id: I0894d1f43127e3776e9f71bd35dcb723a1778ceb
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2356164


> Reviewed-by: John Delaney <johnidel@chromium.org>
> Commit-Queue: Andrew Paseltiner <apaseltiner@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#801381}

Bug: 1099014, 1109599
Change-Id: Ia73fb4cf681524d2ecd2604622c765ac22a21049
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2381254


Reviewed-by: John Delaney <johnidel@chromium.org>
Commit-Queue: Andrew Paseltiner <apaseltiner@chromium.org>
Cr-Commit-Position: refs/heads/master@{#802682}