Old:
  enum Type {
    ClipFirst
    ClipLast
    EndClipFirst
    EndClipLast
    FloatClipFirst
    FloatClipLast
    EndFloatClipFirst
    EndFloatClipLast
    ScrollFirst
    ScrollLast
    EndScrollFirst
    EndScrollLast

New: |k| gets prepended to all the identifiers below.

Problem: This clashes with how macros try to reconstruct the identifiers below and requires the following patch after running the tool:

     // See comments of enum Type for usage of the following macros.
 #define DEFINE_CATEGORY_METHODS(Category) \
-    static bool is##Category##Type(Type type) { return type >= Category##First && type <= Category##Last; } \
+    static bool is##Category##Type(Type type) { return type >= k##Category##First && type <= k##Category##Last; } \
     bool is##Category() const { return is##Category##Type(GetType()); }
 
 #define DEFINE_CONVERSION_METHODS(Category1, category1, Category2, category2) \
     static Type category1##TypeTo##Category2##Type(Type type) \
     { \
-        static_assert(Category1##Last - Category1##First == Category2##Last - Category2##First, \
+        static_assert(k##Category1##Last - k##Category1##First == k##Category2##Last - k##Category2##First, \
             "Categories " #Category1 " and " #Category2 " should have same number of enum values. See comments of DisplayItem::Type"); \
         ASSERT(is##Category1##Type(type)); \
-        return static_cast<Type>(type - Category1##First + Category2##First); \
+        return static_cast<Type>(type - k##Category1##First + k##Category2##First); \
     } \
     static Type category2##TypeTo##Category1##Type(Type type) \
     { \
         ASSERT(is##Category2##Type(type)); \
-        return static_cast<Type>(type - Category2##First + Category1##First); \
+        return static_cast<Type>(type - k##Category2##First + k##Category1##First); \
     }
 
 #define DEFINE_PAIRED_CATEGORY_METHODS(Category, category) \
@@ -271,9 +271,9 @@ public:
 #define DEFINE_PAINT_PHASE_CONVERSION_METHOD(Category) \
     static Type paintPhaseTo##Category##Type(int paint_phase) \
     { \
-        static_assert(Category##PaintPhaseLast - Category##PaintPhaseFirst == kPaintPhaseMax, \
+        static_assert(k##Category##PaintPhaseLast - k##Category##PaintPhaseFirst == kPaintPhaseMax, \
             "Invalid paint-phase-based category " #Category ". See comments of DisplayItem::Type"); \
-        return static_cast<Type>(paint_phase + Category##PaintPhaseFirst); \
+        return static_cast<Type>(paint_phase + k##Category##PaintPhaseFirst); \
     }