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 f720e972846f6a8ad2660a189ebced087facb666..4ce9163780bb2fefb2b1667f32fe95c150409e4e 100644
--- a/runtime/vm/raw_object.h
+++ b/runtime/vm/raw_object.h
@@ -540,6 +540,7 @@ 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:
@@ -584,8 +585,9 @@ 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_);
   }
 };