Immersive fullscreen makes an assumption that TopContainerView is flush with the top edge of the widget (and by extension the display). Introducing kTabstripTopSpacingShortAlternateCaptionButtonStyle broke this assumption.
This CL makes NonClientTopBorderHeight() return 0 for tabbed windows and instead incorporates the border height within the TopContainerView via GetTabStripInsets()

BUG=281766
TEST=ImmersiveModeControllerAshTestWithBrowserView.*

Review URL: https://codereview.chromium.org/24344002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226182 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226182