Win Video Capture: Check returned AM_MEDIA_TYPE pointer before comparing it.

media/video/capture/win/video_capture_device_factory_win.cc

Index: media/video/capture/win/video_capture_device_factory_win.cc
diff --git a/media/video/capture/win/video_capture_device_factory_win.cc b/media/video/capture/win/video_capture_device_factory_win.cc
index 81780d569d324706b04777d6899fe05c665326d1..fee96b8ef72c98da5f94567fffa95e3e7113ca79 100644
--- a/media/video/capture/win/video_capture_device_factory_win.cc
+++ b/media/video/capture/win/video_capture_device_factory_win.cc
@@ -275,7 +275,7 @@ static void GetDeviceSupportedFormatsDirectShow(const Name& device,
     hr = stream_config->GetStreamCaps(i, media_type.Receive(), caps.get());
     // GetStreamCaps() may return S_FALSE, so don't use FAILED() or SUCCEED()
     // macros here since they'll trigger incorrectly.
-    if (hr != S_OK) {
+    if (hr != S_OK || !media_type.get()) {

[tommi (sloooow) - chröme, 2014/10/15 17:23:30]

FYI - I checked the bug and just to confirm - this is exactly what's happening. 
The pointer isn't set by the implementation (which incorrectly returns S_OK), so
media_type wraps a NULL pointer to AM_MEDIA_TYPE and then we attempt to check
the |majortype| member, which is the first member variable of the struct (i.e.
offset 0 from the pointer), and we subsequently deref NULL.

       DLOG(ERROR) << "GetStreamCaps failed: "
                   << logging::SystemErrorCodeToString(hr);
       return;