Move megamorphic cache table into the Dart heap.

runtime/vm/megamorphic_cache_table.h

Index: runtime/vm/megamorphic_cache_table.h
diff --git a/runtime/vm/megamorphic_cache_table.h b/runtime/vm/megamorphic_cache_table.h
index eafb35b12b6ed45d8f656c62668d1518adad1f10..aaf3adc44eeb39bf658009d05c263bf595bfca10 100644
--- a/runtime/vm/megamorphic_cache_table.h
+++ b/runtime/vm/megamorphic_cache_table.h
@@ -11,6 +11,7 @@ namespace dart {
 
 class Array;
 class Function;
+class Isolate;
 class ObjectPointerVisitor;
 class RawArray;
 class RawFunction;
@@ -21,32 +22,25 @@ class String;
 
 class MegamorphicCacheTable {
  public:
-  MegamorphicCacheTable();
-  ~MegamorphicCacheTable();
+  explicit MegamorphicCacheTable(Isolate* isolate) : isolate_(isolate) {}
+  ~MegamorphicCacheTable() {}
 
-  RawFunction* miss_handler() const { return miss_handler_function_; }
+  RawFunction* miss_handler() const;
   void InitMissHandler();
 
   RawMegamorphicCache* Lookup(const String& name, const Array& descriptor);
 
-  void VisitObjectPointers(ObjectPointerVisitor* visitor);
-
   void PrintSizes();
 
  private:
-  struct Entry {
-    RawString* name;
-    RawArray* descriptor;
-    RawMegamorphicCache* cache;
+  enum {
+    kEntryNameOffset = 0,
+    kEntryDescriptorOffset,
+    kEntryCacheOffset,
+    kEntrySize
   };
 
-  static const int kCapacityIncrement = 128;
-
-  RawFunction* miss_handler_function_;
-  RawCode* miss_handler_code_;
-  intptr_t capacity_;
-  intptr_t length_;
-  Entry* table_;
+  Isolate* isolate_;
 
   DISALLOW_COPY_AND_ASSIGN(MegamorphicCacheTable);
 };