Fix and enable the RenderWidgetHostViewAuraTest.SwapNotifiesWindow test

The test should use valid mailboxes and sync points, and the
NoTransportImageTransportFactory should correctly consume the
mailboxes into the ui::Texture.

R=sievers
BUG=347311,270918

Review URL: https://codereview.chromium.org/182253003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253921 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253921