Bug 1208951 - Part 6: Add method to compare nsCSSPropertySets for equality. r=birtles

layout/style/nsCSSPropertySet.h

@@ -8,6 +8,7 @@
 #define nsCSSPropertySet_h__
 
 #include "mozilla/ArrayUtils.h"
+#include "mozilla/PodOperations.h"
 
 #include "nsCSSProperty.h"
 #include <limits.h> // for CHAR_BIT
@@ -62,6 +63,10 @@ public:
         }
     }
 
+    bool Equals(const nsCSSPropertySet& aOther) const {
+      return mozilla::PodEqual(mProperties, aOther.mProperties);
+    }
+
 private:
     typedef unsigned long property_set_type;
 public: