[Windows] Disable warning about mf.dll not being found on Windows

Currently when building a debug configuration of QtWebEngine with
proprietary codecs enabled, running an application will display a
"mf.dll is required for hardware video decoding" warning.
This is due to the fact that the
"DXVAVideoDecodeAccelerator::PreSandboxInitialization" method
which loads the respective shared library is not called at all.

The only call site is in ContentSandboxHelper::PreSandboxStartup,
which is not called by Qt code, because we do not use a separate
GPU process, and the in-process-gpu-thread code lacks the sandbox
initialization.

In Qt's case, adding the missing code to the in-process-gpu thread
does not make sense due to the following reasons:
1) The DXVA accelarator depends on DirectX API being available via
   ANGLE / EGL extensions. When running in Desktop OpenGL mode,
   ANGLE is not available, and thus initialization of DXVA fails.
2) When running in ANGLE mode, Qt disables GPU rendering completely,
   because ANGLE does not support multi-threaded access to OpenGL
   contexts. Because GPU rendering is disabled, so is DXVA support.

Thus this change simply removes the warning output, so as to not
confuse users that something is misconfigured with their QtWebEngine
build.

Change-Id: Ib91f6e4753aa811d366c741cf17220d2892cef2d
Reviewed-by: Kai Koehne <kai.koehne@qt.io>
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

1 files changed, 2 insertions, 0 deletions

diff --git a/chromium/media/gpu/windows/dxva_video_decode_accelerator_win.cc b/chromium/media/gpu/windows/dxva_video_decode_accelerator_win.cc
index d8f1898a085..142398111a3 100644
--- a/chromium/media/gpu/windows/dxva_video_decode_accelerator_win.cc
+++ b/chromium/media/gpu/windows/dxva_video_decode_accelerator_win.cc
@@ -1462,7 +1462,9 @@ DXVAVideoDecodeAccelerator::GetSupportedProfiles(
     if (!::GetModuleHandle(mfdll)) {
       // Windows N is missing the media foundation DLLs unless the media
       // feature pack is installed.
+#if !defined(TOOLKIT_QT)
       DVLOG(ERROR) << mfdll << " is required for hardware video decoding";
+#endif
       return profiles;
     }
   }