diff --git a/layout/base/nsIPresShell.h b/layout/base/nsIPresShell.h
index fe509454f3d..550798f095c 100644
--- a/layout/base/nsIPresShell.h
+++ b/layout/base/nsIPresShell.h
@@ -66,29 +66,22 @@
 #include "nsWeakReference.h"
 #include <stdio.h> // for FILE definition
 
-class nsIAtom;
 class nsIContent;
-class nsIContentIterator;
 class nsIDocument;
-class nsIDocumentObserver;
 class nsIFrame;
 class nsPresContext;
 class nsStyleSet;
 class nsIViewManager;
-class nsIDeviceContext;
 class nsIRenderingContext;
 class nsIPageSequenceFrame;
-class nsString;
 class nsAString;
 class nsCaret;
-class nsStyleContext;
 class nsFrameSelection;
 class nsFrameManager;
 class nsILayoutHistoryState;
 class nsIReflowCallback;
 class nsIDOMNode;
 class nsIRegion;
-class nsIStyleFrameConstruction;
 class nsIStyleSheet;
 class nsCSSFrameConstructor;
 class nsISelection;
@@ -97,7 +90,6 @@ class nsWeakFrame;
 class nsIScrollableFrame;
 class gfxASurface;
 class gfxContext;
-class nsPIDOMEventTarget;
 class nsIDOMEvent;
 class nsDisplayList;
 class nsDisplayListBuilder;
@@ -127,8 +119,8 @@ typedef struct CapturingContentInfo {
 } CapturingContentInfo;
 
 #define NS_IPRESSHELL_IID     \
-{ 0x6736ae7e, 0x25f9, 0x4594, \
-  { 0xb5, 0x26, 0x49, 0x39, 0x17, 0x63, 0x2f, 0x94 } }
+{ 0x84f1a428, 0x6bbe, 0x4958, \
+  { 0xa1, 0x08, 0x8a, 0xe0, 0x78, 0xb8, 0x63, 0xf4 } }
 
 // Constants for ScrollContentIntoView() function
 #define NS_PRESSHELL_SCROLL_TOP      0
@@ -688,12 +680,16 @@ public:
   /**
    * Called to disable nsITheme support in a specific presshell.
    */
-  virtual NS_HIDDEN_(void) DisableThemeSupport() = 0;
+  void DisableThemeSupport()
+  {
+    // Doesn't have to be dynamic.  Just set the bool.
+    mIsThemeSupportDisabled = PR_TRUE;
+  }
 
   /**
    * Indicates whether theme support is enabled.
    */
-  virtual PRBool IsThemeSupportEnabled() = 0;
+  PRBool IsThemeSupportEnabled() const { return !mIsThemeSupportDisabled; }
 
   /**
    * Get the set of agent style sheets for this presentation
@@ -1015,6 +1011,7 @@ protected:
   PRPackedBool              mIsDestroying;
   PRPackedBool              mIsReflowing;
   PRPackedBool              mPaintingSuppressed;  // For all documents we initially lock down painting.
+  PRPackedBool              mIsThemeSupportDisabled;  // Whether or not form controls should use nsITheme in this shell.
 
 #ifdef ACCESSIBILITY
   /**
diff --git a/layout/base/nsPresContext.cpp b/layout/base/nsPresContext.cpp
index ee247d89901..c37b98e265e 100644
--- a/layout/base/nsPresContext.cpp
+++ b/layout/base/nsPresContext.cpp
@@ -1829,13 +1829,8 @@ nsPresContext::GetUserFontSetInternal()
     // that's a bad thing to do, and the caller was responsible for
     // flushing first.  If we're not (e.g., in frame construction), it's
     // ok.
-#ifdef DEBUG
-    {
-      PRBool inReflow;
-      NS_ASSERTION(!userFontSetGottenBefore || !mShell->IsReflowLocked(),
-                   "FlushUserFontSet should have been called first");
-    }
-#endif
+    NS_ASSERTION(!userFontSetGottenBefore || !mShell->IsReflowLocked(),
+                 "FlushUserFontSet should have been called first");
     FlushUserFontSet();
   }
 
diff --git a/layout/base/nsPresShell.cpp b/layout/base/nsPresShell.cpp
index 9dde8f0e4fe..7cd56e0e902 100644
--- a/layout/base/nsPresShell.cpp
+++ b/layout/base/nsPresShell.cpp
@@ -743,9 +743,6 @@ public:
 
   virtual NS_HIDDEN_(void) UnsuppressPainting();
 
-  virtual NS_HIDDEN_(void) DisableThemeSupport();
-  virtual PRBool IsThemeSupportEnabled();
-
   virtual nsresult GetAgentStyleSheets(nsCOMArray<nsIStyleSheet>& aSheets);
   virtual nsresult SetAgentStyleSheets(const nsCOMArray<nsIStyleSheet>& aSheets);
 
@@ -1178,8 +1175,6 @@ protected:
 
   PRPackedBool      mSuppressInterruptibleReflows;
 
-  PRPackedBool      mIsThemeSupportDisabled;  // Whether or not form controls should use nsITheme in this shell.
-
   PRPackedBool      mIsDocumentGone;      // We've been disconnected from the document.
                                           // We will refuse to paint the document until either
                                           // (a) our timer fires or (b) all frames are constructed.
@@ -4426,19 +4421,6 @@ PresShell::UnsuppressPainting()
     UnsuppressAndInvalidate();
 }
 
-void
-PresShell::DisableThemeSupport()
-{
-  // Doesn't have to be dynamic.  Just set the bool.
-  mIsThemeSupportDisabled = PR_TRUE;
-}
-
-PRBool 
-PresShell::IsThemeSupportEnabled()
-{
-  return !mIsThemeSupportDisabled;
-}
-
 // Post a request to handle an arbitrary callback after reflow has finished.
 nsresult
 PresShell::PostReflowCallback(nsIReflowCallback* aCallback)