Revert of Fix RemoteFrame detachment to signal its client. (patchset #1 id:1 of https://codereview.chromium.org/712653002/)

Reason for revert:
Speculative revert to attempt to fix https://code.google.com/p/chromium/issues/detail?id=431608

Original issue's description:
> Fix RemoteFrame detachment to signal its client.
> 
> We were seeing crashes in checkFrameCountConsistency() because during
> RemoteFrame detachment the client was not getting signalled to modify
> the frame tree, resulting in inconsistent state. This CL corrects that
> problem.
> 
> BUG=430972
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=184987

TBR=japhet@chromium.org,dcheng@chromium.org,kenrb@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=430972

Review URL: https://codereview.chromium.org/699053004

git-svn-id: svn://svn.chromium.org/blink/trunk@185015 bbb929c8-8fbe-4397-9dbb-9b2b20218538