Propagate class-id through checked mode type checks.

runtime/vm/intermediate_language.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 1896 matching lines @@
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;
 
   virtual bool CanDeoptimize() const { return false; }
 
   virtual bool HasSideEffect() const { return false; }
 
   virtual bool AffectedBySideEffect() const { return false; }
   virtual bool AttributesEqual(Instruction* other) const;
 
-  virtual intptr_t ResultCid() const { return kDynamicCid; }
+  virtual intptr_t ResultCid() const { return value()->ResultCid(); }
+  virtual intptr_t GetPropagatedCid();
 
   virtual Definition* Canonicalize();
 
  private:
   const intptr_t token_pos_;
   const AbstractType& dst_type_;
   const String& dst_name_;
   bool is_eliminated_;
 
   DISALLOW_COPY_AND_ASSIGN(AssertAssignableInstr);
@@ skipping 2318 matching lines @@
   ForwardInstructionIterator* current_iterator_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_