diff --git a/layout/base/nsPresContext.cpp b/layout/base/nsPresContext.cpp
index 69c24c3b85b..c522731104e 100644
--- a/layout/base/nsPresContext.cpp
+++ b/layout/base/nsPresContext.cpp
@@ -2115,7 +2115,8 @@ nsPresContext::UpdateIsChrome()
 }
 
 /* virtual */ bool
-nsPresContext::HasAuthorSpecifiedRules(nsIFrame *aFrame, uint32_t ruleTypeMask) const
+nsPresContext::HasAuthorSpecifiedRules(const nsIFrame *aFrame,
+                                       uint32_t ruleTypeMask) const
 {
   return
     nsRuleNode::HasAuthorSpecifiedRules(aFrame->StyleContext(),
diff --git a/layout/base/nsPresContext.h b/layout/base/nsPresContext.h
index 91466df89c7..34e98619ea2 100644
--- a/layout/base/nsPresContext.h
+++ b/layout/base/nsPresContext.h
@@ -854,7 +854,8 @@ public:
   void UpdateIsChrome();
 
   // Public API for native theme code to get style internals.
-  virtual bool HasAuthorSpecifiedRules(nsIFrame *aFrame, uint32_t ruleTypeMask) const;
+  virtual bool HasAuthorSpecifiedRules(const nsIFrame *aFrame,
+                                       uint32_t ruleTypeMask) const;
 
   // Is it OK to let the page specify colors and backgrounds?
   bool UseDocumentColors() const {
diff --git a/layout/forms/nsMeterFrame.cpp b/layout/forms/nsMeterFrame.cpp
index 7a8f1dc373f..67adc0deb5b 100644
--- a/layout/forms/nsMeterFrame.cpp
+++ b/layout/forms/nsMeterFrame.cpp
@@ -271,7 +271,7 @@ nsMeterFrame::ShouldUseNativeStyle() const
   //   background.
   return StyleDisplay()->mAppearance == NS_THEME_METERBAR &&
          mBarDiv->GetPrimaryFrame()->StyleDisplay()->mAppearance == NS_THEME_METERBAR_CHUNK &&
-         !PresContext()->HasAuthorSpecifiedRules(const_cast<nsMeterFrame*>(this),
+         !PresContext()->HasAuthorSpecifiedRules(this,
                                                  NS_AUTHOR_SPECIFIED_BORDER | NS_AUTHOR_SPECIFIED_BACKGROUND) &&
          !PresContext()->HasAuthorSpecifiedRules(mBarDiv->GetPrimaryFrame(),
                                                  NS_AUTHOR_SPECIFIED_BORDER | NS_AUTHOR_SPECIFIED_BACKGROUND);
diff --git a/layout/forms/nsProgressFrame.cpp b/layout/forms/nsProgressFrame.cpp
index 1d3fe952792..197adc7e3d1 100644
--- a/layout/forms/nsProgressFrame.cpp
+++ b/layout/forms/nsProgressFrame.cpp
@@ -277,7 +277,7 @@ nsProgressFrame::ShouldUseNativeStyle() const
   //   background.
   return StyleDisplay()->mAppearance == NS_THEME_PROGRESSBAR &&
          mBarDiv->GetPrimaryFrame()->StyleDisplay()->mAppearance == NS_THEME_PROGRESSBAR_CHUNK &&
-         !PresContext()->HasAuthorSpecifiedRules(const_cast<nsProgressFrame*>(this),
+         !PresContext()->HasAuthorSpecifiedRules(this,
                                                  NS_AUTHOR_SPECIFIED_BORDER | NS_AUTHOR_SPECIFIED_BACKGROUND) &&
          !PresContext()->HasAuthorSpecifiedRules(mBarDiv->GetPrimaryFrame(),
                                                  NS_AUTHOR_SPECIFIED_BORDER | NS_AUTHOR_SPECIFIED_BACKGROUND);
diff --git a/layout/forms/nsRangeFrame.cpp b/layout/forms/nsRangeFrame.cpp
index 6d459299c6f..0c1be33e373 100644
--- a/layout/forms/nsRangeFrame.cpp
+++ b/layout/forms/nsRangeFrame.cpp
@@ -838,7 +838,7 @@ bool
 nsRangeFrame::ShouldUseNativeStyle() const
 {
   return (StyleDisplay()->mAppearance == NS_THEME_RANGE) &&
-         !PresContext()->HasAuthorSpecifiedRules(const_cast<nsRangeFrame*>(this),
+         !PresContext()->HasAuthorSpecifiedRules(this,
                                                  (NS_AUTHOR_SPECIFIED_BORDER |
                                                   NS_AUTHOR_SPECIFIED_BACKGROUND)) &&
          !PresContext()->HasAuthorSpecifiedRules(mTrackDiv->GetPrimaryFrame(),