Reland ash: Use immersive mode for fullscreen

* Remove immersive mode button from maximized window frame
* Tie immersive mode to browser-fullscreen only, keep tab-fullscreen
with existing UI
* Size button exits immersive mode
* Add ImageButton::GetImage for testing
* Most browser commands are enabled in immersive fullscreen

BUG=177549
TEST=added to browser_tests views_unittests ash_unittests

Original review: https://codereview.chromium.org/12316086/

Review URL: https://chromiumcodereview.appspot.com/12328119

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@184908 0039d316-1c4b-4281-b951-d872f2087c98
27 files changed