no bug - fixup unused value Werror bustage landed on a CLOSED TREEE

accessible/ipc/other/ProxyAccessible.cpp

@@ -521,13 +521,13 @@ void
 ProxyAccessible::GetColRowExtents(uint32_t* aColIdx, uint32_t* aRowIdx,
                                   uint32_t* aColExtent, uint32_t* aRowExtent)
 {
-  mDoc->SendGetColRowExtents(mID, aColIdx, aRowIdx, aColExtent, aRowExtent);
+  Unused << mDoc->SendGetColRowExtents(mID, aColIdx, aRowIdx, aColExtent, aRowExtent);
 }
 
 void
 ProxyAccessible::GetPosition(uint32_t* aColIdx, uint32_t* aRowIdx)
 {
-  mDoc->SendGetPosition(mID, aColIdx, aRowIdx);
+  Unused << mDoc->SendGetPosition(mID, aColIdx, aRowIdx);
 }
 
 uint32_t