Add tests of texture frames in video_send_stream_test.

Also fix a bug in ViEFrameProviderBase::DeliverFrame that
a texture frame was only delivered to the first callback.

BUG=chromium:362437
TEST=Run video engine test and webrtc call on CrOS.
R=kjellander@webrtc.org, pbos@webrtc.org, stefan@webrtc.org, wuchengli@google.com

Review URL: https://webrtc-codereview.appspot.com/15789004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6506 4adac7df-926f-26a2-2b94-8c16560cd09d