[ic] Simplify handling of primitive maps.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 9249d8b3f56cf1cedcb7266cbcecbc364e43dd7a..8d17e63a60a806860470460da4d96a124abe15b2 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -1559,7 +1559,7 @@ class Object {
   friend class StringStream;
 
   // Return the map of the root of object's prototype chain.
-  Map* GetRootMap(Isolate* isolate);
+  Map* GetPrototypeChainRootMap(Isolate* isolate);
 
   // Helper for SetProperty and SetSuperProperty.
   // Return value is only meaningful if [found] is set to true on return.
@@ -6332,6 +6332,9 @@ class Map: public HeapObject {
   static const int kPrototypeChainValid = 0;
   static const int kPrototypeChainInvalid = 1;
 
+  // Return the map of the root of object's prototype chain.
+  Map* GetPrototypeChainRootMap(Isolate* isolate);
+
   // Returns a WeakCell object containing given prototype. The cell is cached
   // in PrototypeInfo which is created lazily.
   static Handle<WeakCell> GetOrCreatePrototypeWeakCell(