--- a/layout/base/nsPresArena.cpp
+++ b/layout/base/nsPresArena.cpp
@@ -155,22 +155,16 @@ nsPresArena::AddSizeOfExcludingThis(nsWi
         break;
 #define ABSTRACT_FRAME_ID(...)
 #include "nsFrameIdList.h"
 #undef FRAME_ID
 #undef ABSTRACT_FRAME_ID
       case eArenaObjectID_nsLineBox:
         aSizes.mArenaSizes.mLineBoxes += totalSize;
         break;
-      case eArenaObjectID_nsRuleNode:
-        aSizes.mArenaSizes.mRuleNodes += totalSize;
-        break;
-      case eArenaObjectID_GeckoComputedStyle:
-        aSizes.mArenaSizes.mComputedStyles += totalSize;
-        break;
       default:
         continue;
     }
 
     totalSizeInFreeLists += totalSize;
   }
 
   aSizes.mLayoutPresShellSize += mallocSize - totalSizeInFreeLists;

--- a/layout/base/nsPresArenaObjectList.h
+++ b/layout/base/nsPresArenaObjectList.h
@@ -4,20 +4,17 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /* a list of all types that can be allocated in an nsPresArena, for
    preprocessing */
 
 // These are objects that can be stored in the pres arena
 
-PRES_ARENA_OBJECT(GeckoComputedStyle)
-
 PRES_ARENA_OBJECT(nsLineBox)
-PRES_ARENA_OBJECT(nsRuleNode)
 PRES_ARENA_OBJECT(DisplayItemData)
 PRES_ARENA_OBJECT(nsInheritedStyleData)
 PRES_ARENA_OBJECT(nsResetStyleData)
 PRES_ARENA_OBJECT(nsConditionalResetStyleData)
 PRES_ARENA_OBJECT(nsConditionalResetStyleDataEntry)
 PRES_ARENA_OBJECT(nsFrameList)
 PRES_ARENA_OBJECT(CustomCounterStyle)
 PRES_ARENA_OBJECT(DependentBuiltinCounterStyle)