Clean JS function results cache on each major GC.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 48be90217ef36d32d2d2034acf86fdfc4451945e..a728f0695e988861a5258b444ab8abdd16eca206 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -606,6 +606,7 @@ class Object BASE_EMBEDDED {
   inline bool IsHashTable();
   inline bool IsDictionary();
   inline bool IsSymbolTable();
+  inline bool IsJSFunctionResultCache();
   inline bool IsCompilationCacheTable();
   inline bool IsCodeCacheHashTable();
   inline bool IsMapCache();
@@ -2326,6 +2327,16 @@ class JSFunctionResultCache: public FixedArray {
   static const int kEntriesIndex = kDummyIndex + 1;
 
   static const int kEntrySize = 2;  // key + value
+
+  inline void MakeZeroSize();
+  inline void Clear();
+
+  // Casting
+  static inline JSFunctionResultCache* cast(Object* obj);
+
+#ifdef DEBUG
+  void JSFunctionResultCacheVerify();
+#endif
 };