Updating trunk VERSION from 1638.0 to 1639.0

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224556 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 224556
Maximize a tab dragged from a maximized window
This affects behavior on all platforms not just ash.

BUG=171435
TEST=interactive_ui_tests --gtest_filter=*DetachToOwnWindowFromMaximizedWindow*
TEST=interactive_ui_tests --gtest_filter=*DragInMaximizedWindow*

Review URL: https://chromiumcodereview.appspot.com/23620059

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224558 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 224558