Fix Cmd-W closing whole window under fullscreen.

This got broken by http://crrev.com/116144, which made Cmd-W
(close tab) route to -performClose:.

However, FullscreenWindow had an override for -performClose:,
resulting in the logic to route Cmd-W to -commandDispatch: not
taking place for fullscreen windows.

Also fixes -[BWC validateUserInterfaceItem:] to correctly disable
IDC_CLOSE_TAB menu items, which was also broken in the same
revision.

BUG=109793
TEST=1. Open a fullscreen window with multiple tabs. Hit Cmd-W. A single tab should close.
2. Open a window that doesn't have tabs - e.g. Window -> Task Manager. File -> Close Tab
should be disabled.

Review URL: http://codereview.chromium.org/9187063

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@117681 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed