Fix -Wunused-but-set-variable.

This is part of a set of CLs to fix the Chromium roll.

Bug: None
Change-Id: I3b00a4051b4219f8338986ebc4c69fa8318920de
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/236681
Commit-Queue: Tommi <tommi@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35286}
diff --git a/modules/video_capture/windows/help_functions_ds.cc b/modules/video_capture/windows/help_functions_ds.cc
index 58b9de9..b767726 100644
--- a/modules/video_capture/windows/help_functions_ds.cc
+++ b/modules/video_capture/windows/help_functions_ds.cc
@@ -30,7 +30,6 @@
 }
 
 IPin* GetInputPin(IBaseFilter* filter) {
-  HRESULT hr;
   IPin* pin = NULL;
   IEnumPins* pPinEnum = NULL;
   filter->EnumPins(&pPinEnum);
@@ -39,7 +38,7 @@
   }
 
   // get first unconnected pin
-  hr = pPinEnum->Reset();  // set to first pin
+  pPinEnum->Reset();  // set to first pin
 
   while (S_OK == pPinEnum->Next(1, &pin, NULL)) {
     PIN_DIRECTION pPinDir;