InstantExtended: Remove overlay control code.

InstantExtended: Remove overlay control code.

This change deletes the browser-side InstantController code pertaining
to old Instant, the HTML popup and search results overlay. A lot of UI
and renderer code is still lingering and doing nothing, but I'll get
that in another CL.

TEST=Manually. Verify that InstantExtended NTP and searching works, and
that normal Chrome is unaffected.
BUG=251262
TBR=samarth@chromium.org,pkasting@chromium.org,brettw@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=210062

[Jered, 2013-07-03 21:24:46]

My previous attempt in 18223002 got reverted because it broke the rlz build
(which evidently is not tested in CQ at all). I've fixed that issue so will try
submitting this again.

[Jered, 2013-07-03 23:09:19]

Committed patchset #3 manually as r210062 (presubmit successful).