Change all callers of nsIPresContext::GetShell() to use the non-refcounting versions. Most callers now use PresShell(), a few that were checking for null conditions are using GetPresShell() -- this will be remedied once we can ensure that a prescontext never has a null pres shell. Bug 227690, r+sr=bzbarsky.

widget/src/mac/nsNativeThemeMac.cpp

@@ -756,12 +756,8 @@ nsNativeThemeMac::ThemeSupportsWidget(nsIPresContext* aPresContext, nsIFrame* aF
     return PR_FALSE;
 #endif
 
-  if (aPresContext) {
-    nsCOMPtr<nsIPresShell> shell;
-    aPresContext->GetShell(getter_AddRefs(shell));
-    if (!shell->IsThemeSupportEnabled())
-      return PR_FALSE;
-  }
+  if (aPresContext && !aPresContext->PresShell()->IsThemeSupportEnabled())
+    return PR_FALSE;
 
   PRBool retVal = PR_FALSE;
   

widget/src/windows/nsNativeThemeWin.cpp

@@ -1152,12 +1152,8 @@ nsNativeThemeWin::ThemeSupportsWidget(nsIPresContext* aPresContext,
   // XXXdwh We can go even further and call the API to ask if support exists for
   // specific widgets.
 
-  if (aPresContext) {
-    nsCOMPtr<nsIPresShell> shell;
-    aPresContext->GetShell(getter_AddRefs(shell));
-    if (!shell->IsThemeSupportEnabled())
-      return PR_FALSE;
-  }
+  if (aPresContext && !aPresContext->PresShell()->IsThemeSupportEnabled())
+    return PR_FALSE;
 
   HANDLE theme = NULL;
   if (aWidgetType == NS_THEME_CHECKBOX_CONTAINER)