Account for short-circuited resizes in Content Shell.
When running layout tests, we short-circuit our window-positioning
machinery to stay within the rendering process. This means that
we should similarly short-circuit sizing of the newly opened
secondary windows. Otherwise, a race occurs and occasionally,
a resize to 0x0 message arrives from the browser process.
BUG=307570
R=jam, jochen, tony
Review URL: https://codereview.chromium.org/
29233005
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229681 0039d316-1c4b-4281-b951-d872f2087c98