Revert of DevTools: Do not save split view size on show mode changes. (https://codereview.chromium.org/185943004/)

Reason for revert:
Split location is no longer persisted.

Original issue's description:
> DevTools: Do not save split view size on show mode changes.
> 
> BUG=348887
> R=dgozman
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=168608

TBR=dgozman@chromium.org,vsevik@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=348887

Review URL: https://codereview.chromium.org/185063005

git-svn-id: svn://svn.chromium.org/blink/trunk@168626 bbb929c8-8fbe-4397-9dbb-9b2b20218538