Fix window capturer not to leak HDC.

Previously Windows window capturer kept DC handles between captures. As
result it was leaking DC handles in SelectWindow(). Fixed it so that it
calls GetWindowDC() for each capture.

R=alexeypa@chromium.org

Review URL: https://webrtc-codereview.appspot.com/2289004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@4834 4adac7df-926f-26a2-2b94-8c16560cd09d
1 file changed