Bug 1308792 - clear DeviceInfoDSSingleton::GetInfo() in DeviceInfoDS dtor to prevent illegal access crash; r=jesup,jib

MozReview-Commit-ID: Fy6Qu6sONgr

media/webrtc/trunk/webrtc/modules/video_capture/windows/device_info_ds.cc

@@ -156,6 +156,7 @@ DeviceInfoDS::~DeviceInfoDS()
         DestroyWindow(_hwnd);
     }
     UnregisterClass(_wndClass.lpszClassName, _hInstance);
+    DeviceInfoDSSingleton::GetInfo() = NULL;
 }
 
 int32_t DeviceInfoDS::Init()