Save port forwarding configuration on every edit in chrome://inspect.

BUG=281250

Review URL: https://codereview.chromium.org/32123002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230127 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 230127