Compute NativeBehavior for native methods and fields.

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

Index: pkg/compiler/lib/src/ssa/builder.dart
diff --git a/pkg/compiler/lib/src/ssa/builder.dart b/pkg/compiler/lib/src/ssa/builder.dart
index 9e17d7a9a503202de4c087bd2b3aba3d73dcb598..bc108a20a095cfcf11c46ec351758be49a7d77c8 100644
--- a/pkg/compiler/lib/src/ssa/builder.dart
+++ b/pkg/compiler/lib/src/ssa/builder.dart
@@ -3064,7 +3064,7 @@ class SsaBuilder extends ast.Visitor
 
   void handleForeignSend(ast.Send node, FunctionElement element) {
     String name = element.name;
-    if (name == 'JS') {
+    if (name == BackendHelpers.JS) {
       handleForeignJs(node);
     } else if (name == 'JS_CURRENT_ISOLATE_CONTEXT') {
       handleForeignJsCurrentIsolateContext(node);
@@ -3080,15 +3080,15 @@ class SsaBuilder extends ast.Visitor
       handleForeignJsGetStaticState(node);
     } else if (name == 'JS_GET_NAME') {
       handleForeignJsGetName(node);
-    } else if (name == 'JS_EMBEDDED_GLOBAL') {
+    } else if (name == BackendHelpers.JS_EMBEDDED_GLOBAL) {
       handleForeignJsEmbeddedGlobal(node);
-    } else if (name == 'JS_BUILTIN') {
+    } else if (name == BackendHelpers.JS_BUILTIN) {
       handleForeignJsBuiltin(node);
     } else if (name == 'JS_GET_FLAG') {
       handleForeignJsGetFlag(node);
     } else if (name == 'JS_EFFECT') {
       stack.add(graph.addConstantNull(compiler));
-    } else if (name == 'JS_INTERCEPTOR_CONSTANT') {
+    } else if (name == BackendHelpers.JS_INTERCEPTOR_CONSTANT) {
       handleJsInterceptorConstant(node);
     } else if (name == 'JS_STRING_CONCAT') {
       handleJsStringConcat(node);