VM: [Kernel] Add kernel::ConstantEvaluator support for string.length

runtime/vm/kernel_to_il.h

 // Copyright (c) 2016, 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 RUNTIME_VM_KERNEL_TO_IL_H_
 #define RUNTIME_VM_KERNEL_TO_IL_H_
 
 #if !defined(DART_PRECOMPILED_RUNTIME)
 
 #include "vm/growable_array.h"
@@ skipping 396 matching lines @@
   virtual void VisitConstructorInvocation(ConstructorInvocation* node);
   virtual void VisitMethodInvocation(MethodInvocation* node);
   virtual void VisitStaticGet(StaticGet* node);
   virtual void VisitVariableGet(VariableGet* node);
   virtual void VisitLet(Let* node);
   virtual void VisitStaticInvocation(StaticInvocation* node);
   virtual void VisitStringConcatenation(StringConcatenation* node);
   virtual void VisitConditionalExpression(ConditionalExpression* node);
   virtual void VisitLogicalExpression(LogicalExpression* node);
   virtual void VisitNot(Not* node);
+  virtual void VisitPropertyGet(PropertyGet* node);
 
  private:
   // This will translate type arguments form [kernel_arguments].  If no type
   // arguments are passed and the [target] is a factory then the null type
   // argument array will be returned.
   //
   // If none of these cases apply, NULL will be returned.
   const TypeArguments* TranslateTypeArguments(const Function& target,
                                               dart::Class* target_klass,
                                               Arguments* kernel_arguments);
@@ skipping 515 matching lines @@
   friend class SwitchBlock;
   friend class TryCatchBlock;
   friend class TryFinallyBlock;
 };
 
 }  // namespace kernel
 }  // namespace dart
 
 #endif  // !defined(DART_PRECOMPILED_RUNTIME)
 #endif  // RUNTIME_VM_KERNEL_TO_IL_H_