Split HForeign into HForeignCode and abstract base class.

pkg/compiler/lib/src/native/ssa.dart

 // Copyright (c) 2014, 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.
 
 part of native;
 
 final RegExp nativeRedirectionRegExp = new RegExp(r'^[a-zA-Z][a-zA-Z_$0-9]*$');
 
 void handleSsaNative(SsaBuilder builder, Expression nativeBody) {
   Compiler compiler = builder.compiler;
@@ skipping 67 matching lines @@
     } else if (element.kind == ElementKind.GETTER) {
       nativeMethodCall = '$receiver$nativeMethodName';
     } else if (element.kind == ElementKind.SETTER) {
       nativeMethodCall = '$receiver$nativeMethodName = $foreignParameters';
     } else {
       builder.compiler.internalError(element,
                                      'Unexpected kind: "${element.kind}".');
     }
 
     builder.push(
-        new HForeign(
+        new HForeignCode(
             // TODO(sra): This could be cached.  The number of templates should
             // be proportional to the number of native methods, which is bounded
             // by the dart: libraries.
             js.js.uncachedExpressionTemplate(nativeMethodCall),
             backend.dynamicType,
             inputs, effects: new SideEffects()));
     builder.close(new HReturn(builder.pop())).addSuccessor(builder.graph.exit);
   } else {
     if (parameters.parameterCount != 0) {
       compiler.internalError(nativeBody,
           'native "..." syntax is restricted to '
           'functions with zero parameters.');
     }
     LiteralString jsCode = nativeBody.asLiteralString();
-    builder.push(new HForeign.statement(
+    builder.push(new HForeignCode.statement(
         js.js.statementTemplateYielding(
             new js.LiteralStatement(jsCode.dartString.slowToString())),
         <HInstruction>[],
         new SideEffects(),
         null,
         backend.dynamicType));
   }
 }