Revert 248072 "It2me native messaging host: webapp implementation."

> It2me native messaging host: webapp implementation.
> 
> The webapp implementation of the it2me native messaging is based on the me2me couterpart. But I got rid of the per-message onDone/onError callbacks because unlike me2me, all requests to the it2me host are asynchronous: direct responses to all requests are meaningless. Only the asynchronous callbacks on host state change and nat policy update need to be processed.
> 
> I verified that this is fully functional on Linux. Windows and Mac verification haven't been done and are planned after the linux work is completed.
> 
> BUG=309844
> 
> Review URL: https://codereview.chromium.org/138503009

TBR=weitaosu@chromium.org

Review URL: https://codereview.chromium.org/142703009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248096 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248096
Refactor OpaqueBrowserFrameView; reduce uses of kUseSystemTitleBar.

This brings the number of places in the codebase that use the
kUseSystemTitleBar switch variable down to two (down from five).

This will reduce the number of places that need to be changed to replace
this flag with a preference.

BUG=317859

Review URL: https://codereview.chromium.org/146343002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248097 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248097