Create and cache method extraction stub in the ICData.

runtime/vm/raw_object.h

Index: runtime/vm/raw_object.h
diff --git a/runtime/vm/raw_object.h b/runtime/vm/raw_object.h
index d4c9a6002d4ee374c703a40c164c5d25fb18ef58..cac0862e46856cd76c4f725140c316921ad8f458 100644
--- a/runtime/vm/raw_object.h
+++ b/runtime/vm/raw_object.h
@@ -539,6 +539,7 @@ class RawFunction : public RawObject {
     kImplicitGetter,     // represents an implicit getter for fields.
     kImplicitSetter,     // represents an implicit setter for fields.
     kConstImplicitGetter,  // represents an implicit const getter for fields.
+    kMethodExtractor,  // converts method into implicit closure on the receiver.
   };
 
  private:
@@ -583,8 +584,9 @@ class RawClosureData : public RawObject {
     RawInstance* closure_;  // Closure object for static implicit closures.
     RawCode* closure_allocation_stub_;  // Stub code for allocation of closures.
   };
+  RawFunction* method_extractor_;  // Stub code for method extraction.
   RawObject** to() {
-    return reinterpret_cast<RawObject**>(&ptr()->closure_allocation_stub_);
+    return reinterpret_cast<RawObject**>(&ptr()->method_extractor_);
   }
 };