Stop assuming anything about result of MFStartup()

media/capture/video/win/video_capture_device_factory_win.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/capture/video/win/video_capture_device_factory_win.h"
 
 #include <mfapi.h>
 #include <mferror.h>
 #include <stddef.h>
 
@@ skipping 61 matching lines @@
     ExpandEnvironmentStringsW(kMfDLL, path, arraysize(path));
     if (!LoadLibraryExW(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH))
       return false;
   }
   return true;
 }
 
 static bool PrepareVideoCaptureAttributesMediaFoundation(
     IMFAttributes** attributes,
     int count) {
-  InitializeMediaFoundation();
+  if (!InitializeMediaFoundation())
+    return false;
 
   if (FAILED(MFCreateAttributes(attributes, count)))
     return false;
 
   return SUCCEEDED(
       (*attributes)
           ->SetGUID(MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE,
                     MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_VIDCAP_GUID));
 }
 
@@ skipping 366 matching lines @@
 }
 
 // static
 VideoCaptureDeviceFactory*
 VideoCaptureDeviceFactory::CreateVideoCaptureDeviceFactory(
     scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner) {
   return new VideoCaptureDeviceFactoryWin();
 }
 
 }  // namespace media