dart2js: simplify constant expression generation.

pkg/compiler/lib/src/js_emitter/code_emitter_task.dart

Index: pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
diff --git a/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart b/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
index 7f64f57240087eb3497ec166fc84d133048d6e6a..3572ff417d7d49622697c6f5046a633eea5acfa9 100644
--- a/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
+++ b/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
@@ -417,9 +417,6 @@ abstract class Emitter {
   /// Returns the JS code for accessing the embedded [global].
   jsAst.Expression generateEmbeddedGlobalAccess(String global);
 
-  /// Returns the JS code for accessing the given [constant].
-  jsAst.Expression constantReference(ConstantValue constant);
-
   /// Returns the JS function representing the given function.
   ///
   /// The function must be invoked and can not be used as closure.
@@ -447,5 +444,8 @@ abstract class Emitter {
   int compareConstants(ConstantValue a, ConstantValue b);
   bool isConstantInlinedOrAlreadyEmitted(ConstantValue constant);
 
+  /// Returns the JS code for accessing the given [constant].
+  jsAst.Expression constantReference(ConstantValue constant);
+
   void invalidateCaches();
 }