Revert of Enable virtual viewport on all platforms (patchset #5 id:80001 of https://codereview.chromium.org/665963002/)

Reason for revert:
This appears to break the entire world as far as LayoutTests are concerned. Here's a small sample: http://test-results.appspot.com/dashboards/flakiness_dashboard.html#showExpectations=true&tests=css1%2Fbasic%2Fcontainment.html%2Ccss1%2Fbasic%2Fcomments.html%2Ccss1%2Fbasic%2Fgrouping.html%2Ccss1%2Fbasic%2Fclass_as_selector.html%2Ccss1%2Fbasic%2Finheritance.html%2Ccss1%2Fbasic%2Fcontextual_selectors.html%2Ccss1%2Fbasic%2Fid_as_selector.html

Original issue's description:
> Enable virtual viewport on all platforms except Android WebView.
>
> BUG=148816
>
> Committed: https://crrev.com/e52372c24d2e1e9785703f0563ffc3423f7161cc
> Cr-Commit-Position: refs/heads/master@{#301307}

TBR=aelias@chromium.org,mkosiba@chromium.org,cpu@chromium.org,bokan@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=148816

Review URL: https://codereview.chromium.org/679973003

Cr-Commit-Position: refs/heads/master@{#301311}
2 files changed