diff --git a/layout/style/nsComputedDOMStyle.cpp b/layout/style/nsComputedDOMStyle.cpp
index f978e5a0081e..e9424340cb82 100644
--- a/layout/style/nsComputedDOMStyle.cpp
+++ b/layout/style/nsComputedDOMStyle.cpp
@@ -308,10 +308,6 @@ nsComputedDOMStyle::nsComputedDOMStyle(dom::Element* aElement,
       mStyleType(aStyleType),
       mExposeVisitedStyle(false),
       mResolvedComputedStyle(false)
-#ifdef DEBUG
-      ,
-      mFlushedPendingReflows(false)
-#endif
 {
   MOZ_ASSERT(aElement);
   MOZ_ASSERT(aDocument);
diff --git a/layout/style/nsComputedDOMStyle.h b/layout/style/nsComputedDOMStyle.h
index 9dc225d6ad9b..55e06e728808 100644
--- a/layout/style/nsComputedDOMStyle.h
+++ b/layout/style/nsComputedDOMStyle.h
@@ -406,7 +406,7 @@ class nsComputedDOMStyle final : public nsDOMCSSDeclaration,
   bool mResolvedComputedStyle;
 
 #ifdef DEBUG
-  bool mFlushedPendingReflows;
+  bool mFlushedPendingReflows = false;
 #endif
 
   friend struct ComputedStyleMap;