Removing an invalid assert that may get fired during display reconfiguration.

BUG=https://code.google.com/p/webrtc/issues/detail?id=2787

Review URL: https://codereview.chromium.org/138933007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248328 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248328