--- a/layout/style/ComputedStyle.h
+++ b/layout/style/ComputedStyle.h
@@ -14,16 +14,62 @@
 #include "mozilla/Assertions.h"
 #include "mozilla/RestyleLogging.h"
 #include "mozilla/ServoStyleSet.h"
 #include "mozilla/ServoUtils.h"
 #include "mozilla/StyleComplexColor.h"
 #include "mozilla/CachedInheritingStyles.h"
 #include "nsCSSAnonBoxes.h"
 
+// Includes nsStyleStructID.
+#include "nsStyleStructFwd.h"
+
+// Bits for each struct.
+// NS_STYLE_INHERIT_BIT defined in nsStyleStructFwd.h
+#define NS_STYLE_INHERIT_MASK              0x000ffffff
+
+// Bits for inherited structs.
+#define NS_STYLE_INHERITED_STRUCT_MASK \
+  ((nsStyleStructID_size_t(1) << nsStyleStructID_Inherited_Count) - 1)
+// Bits for reset structs.
+#define NS_STYLE_RESET_STRUCT_MASK \
+  (((nsStyleStructID_size_t(1) << nsStyleStructID_Reset_Count) - 1) \
+   << nsStyleStructID_Inherited_Count)
+
+// Additional bits for ComputedStyle's mBits:
+// See ComputedStyle::HasTextDecorationLines
+#define NS_STYLE_HAS_TEXT_DECORATION_LINES 0x001000000
+// See ComputedStyle::HasPseudoElementData.
+#define NS_STYLE_HAS_PSEUDO_ELEMENT_DATA   0x002000000
+// See ComputedStyle::RelevantLinkIsVisited
+#define NS_STYLE_RELEVANT_LINK_VISITED     0x004000000
+// See ComputedStyle::IsStyleIfVisited
+#define NS_STYLE_IS_STYLE_IF_VISITED       0x008000000
+// See ComputedStyle::HasChildThatUsesGrandancestorStyle
+#define NS_STYLE_CHILD_USES_GRANDANCESTOR_STYLE 0x010000000
+// See ComputedStyle::IsShared
+#define NS_STYLE_IS_SHARED                 0x020000000
+// See ComputedStyle::AssertStructsNotUsedElsewhere
+// (This bit is currently only used in #ifdef DEBUG code.)
+#define NS_STYLE_IS_GOING_AWAY             0x040000000
+// See ComputedStyle::ShouldSuppressLineBreak
+#define NS_STYLE_SUPPRESS_LINEBREAK        0x080000000
+// See ComputedStyle::IsInDisplayNoneSubtree
+#define NS_STYLE_IN_DISPLAY_NONE_SUBTREE   0x100000000
+// See ComputedStyle::FindChildWithRules
+#define NS_STYLE_INELIGIBLE_FOR_SHARING    0x200000000
+// See ComputedStyle::HasChildThatUsesResetStyle
+#define NS_STYLE_HAS_CHILD_THAT_USES_RESET_STYLE 0x400000000
+// See ComputedStyle::IsTextCombined
+#define NS_STYLE_IS_TEXT_COMBINED          0x800000000
+// Whether a ComputedStyle is a Gecko or Servo context
+#define NS_STYLE_CONTEXT_IS_GECKO          0x1000000000
+// See ComputedStyle::GetPseudoEnum
+#define NS_STYLE_CONTEXT_TYPE_SHIFT        37
+
 class nsAtom;
 class nsPresContext;
 class nsWindowSizes;
 
 namespace mozilla {
 
 enum class CSSPseudoElementType : uint8_t;
 class ComputedStyle;

--- a/layout/style/nsStyleStruct.h
+++ b/layout/style/nsStyleStruct.h
@@ -46,62 +46,16 @@ class nsPresContext;
 struct nsStyleVisibility;
 namespace mozilla {
 class ComputedStyle;
 namespace dom {
 class ImageTracker;
 } // namespace dom
 } // namespace mozilla
 
-// Includes nsStyleStructID.
-#include "nsStyleStructFwd.h"
-
-// Bits for each struct.
-// NS_STYLE_INHERIT_BIT defined in nsStyleStructFwd.h
-#define NS_STYLE_INHERIT_MASK              0x000ffffff
-
-// Bits for inherited structs.
-#define NS_STYLE_INHERITED_STRUCT_MASK \
-  ((nsStyleStructID_size_t(1) << nsStyleStructID_Inherited_Count) - 1)
-// Bits for reset structs.
-#define NS_STYLE_RESET_STRUCT_MASK \
-  (((nsStyleStructID_size_t(1) << nsStyleStructID_Reset_Count) - 1) \
-   << nsStyleStructID_Inherited_Count)
-
-// Additional bits for ComputedStyle's mBits:
-// See ComputedStyle::HasTextDecorationLines
-#define NS_STYLE_HAS_TEXT_DECORATION_LINES 0x001000000
-// See ComputedStyle::HasPseudoElementData.
-#define NS_STYLE_HAS_PSEUDO_ELEMENT_DATA   0x002000000
-// See ComputedStyle::RelevantLinkIsVisited
-#define NS_STYLE_RELEVANT_LINK_VISITED     0x004000000
-// See ComputedStyle::IsStyleIfVisited
-#define NS_STYLE_IS_STYLE_IF_VISITED       0x008000000
-// See ComputedStyle::HasChildThatUsesGrandancestorStyle
-#define NS_STYLE_CHILD_USES_GRANDANCESTOR_STYLE 0x010000000
-// See ComputedStyle::IsShared
-#define NS_STYLE_IS_SHARED                 0x020000000
-// See ComputedStyle::AssertStructsNotUsedElsewhere
-// (This bit is currently only used in #ifdef DEBUG code.)
-#define NS_STYLE_IS_GOING_AWAY             0x040000000
-// See ComputedStyle::ShouldSuppressLineBreak
-#define NS_STYLE_SUPPRESS_LINEBREAK        0x080000000
-// See ComputedStyle::IsInDisplayNoneSubtree
-#define NS_STYLE_IN_DISPLAY_NONE_SUBTREE   0x100000000
-// See ComputedStyle::FindChildWithRules
-#define NS_STYLE_INELIGIBLE_FOR_SHARING    0x200000000
-// See ComputedStyle::HasChildThatUsesResetStyle
-#define NS_STYLE_HAS_CHILD_THAT_USES_RESET_STYLE 0x400000000
-// See ComputedStyle::IsTextCombined
-#define NS_STYLE_IS_TEXT_COMBINED          0x800000000
-// Whether a ComputedStyle is a Gecko or Servo context
-#define NS_STYLE_CONTEXT_IS_GECKO          0x1000000000
-// See ComputedStyle::GetPseudoEnum
-#define NS_STYLE_CONTEXT_TYPE_SHIFT        37
-
 namespace mozilla {
 
 struct Position {
   using Coord = nsStyleCoord::CalcValue;
 
   Coord mXPosition, mYPosition;
 
   // Initialize nothing