Revert 242936 "When stopping QTKit video capture, call stopRunni..."

Revert 242936 "When stopping QTKit video capture, call stopRunni..."

This CL removed a deadlock on camera removal, but created a new one
on shutdown while a camera is running.

> When stopping QTKit video capture, call stopRunning before removeInput:.
> 
> Empirically, this prevents a browser hang when the active camera is
> unplugged.  The unplug event triggers both stopping the capturer and
> enumerating the available input devices at the same time.  It seems
> that calling removeInput: on a running capturer after an error
> produces a deadlock, but stopping the capturer first resolves the
> problem.
> 
> BUG=285053
> 
> Review URL: https://codereview.chromium.org/120963003

TBR=bemasc@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=243445

[bemasc, 2014-01-08 00:29:24]

Committed patchset #1 manually as r243445.