Fix for bug #2867. Removed the questionable logic I added previously.

layout/generic/nsHTMLFrame.cpp

@@ -67,7 +67,7 @@ public:
                          nsGUIEvent*     aEvent,
                          nsEventStatus&  aEventStatus);
   NS_IMETHOD IsPercentageBase(PRBool& aBase) const {
-    aBase = PR_FALSE;
+    aBase = PR_TRUE;
     return NS_OK;
   }
 

layout/html/base/src/nsHTMLFrame.cpp

@@ -67,7 +67,7 @@ public:
                          nsGUIEvent*     aEvent,
                          nsEventStatus&  aEventStatus);
   NS_IMETHOD IsPercentageBase(PRBool& aBase) const {
-    aBase = PR_FALSE;
+    aBase = PR_TRUE;
     return NS_OK;
   }