RFC: Start refactoring to provide more than a single backend.

lib/compiler/implementation/emitter.dart

Index: lib/compiler/implementation/emitter.dart
diff --git a/lib/compiler/implementation/emitter.dart b/lib/compiler/implementation/emitter.dart
index e5762dd39ff38c95bd02a3bde13dea9485019b6b..79231b25005c62ea3bfb85d87fbbe6d782b62d4f 100644
--- a/lib/compiler/implementation/emitter.dart
+++ b/lib/compiler/implementation/emitter.dart
@@ -777,13 +777,13 @@ function() {
     if (member.kind == ElementKind.GETTER || member.kind == ElementKind.FIELD) {
       Set<Selector> selectors = compiler.universe.invokedNames[member.name];
       if (selectors !== null && !selectors.isEmpty()) {
-        compiler.emitter.emitCallStubForGetter(member, selectors,
-                                               defineInstanceMember);
+        compiler.backend.emitter.emitCallStubForGetter(
+            member, selectors, defineInstanceMember);
       }
     } else if (member.kind == ElementKind.FUNCTION) {
       if (compiler.universe.hasGetter(member, compiler)) {
-        compiler.emitter.emitDynamicFunctionGetter(member,
-                                                   defineInstanceMember);
+        compiler.backend.emitter.emitDynamicFunctionGetter(
+            member, defineInstanceMember);
       }
     }
   }