Implement apps v2 custom window frame.
The default apps v2 container is pretty basic. We want to provide something that looks prettier and also implements some functionality specific to our use-case:
* When connected to a host, a disconnect icon is added to the window controls (it's therefore no longer needed in the tool-bar).
* When connected to a host, maximize == full-screen.
* In full-screen mode, the window controls are still accessible, but are auto-hidden near the top-left corner (but not obscuring it, since it's often a hot-spot on the server).
* For touch-screen devices with no concept of hover, clicking the "stub" will also reveal the controls.
There should be no change to the v1 UX, but I don't plan on landing this CL before the M36 branch point, just in case.
BUG=134213
Review URL: https://codereview.chromium.org/
265393005
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@270342 0039d316-1c4b-4281-b951-d872f2087c98