Extract DiagnosticReporter implementation from Compiler.

pkg/compiler/lib/src/js_backend/no_such_method_registry.dart

Index: pkg/compiler/lib/src/js_backend/no_such_method_registry.dart
diff --git a/pkg/compiler/lib/src/js_backend/no_such_method_registry.dart b/pkg/compiler/lib/src/js_backend/no_such_method_registry.dart
index 0a322bdb03fea62e00e3b5ed957c9faf4b3cc9be..3bb7e4502bf0f0cf08e0b9a1f92278ae1e1c09f6 100644
--- a/pkg/compiler/lib/src/js_backend/no_such_method_registry.dart
+++ b/pkg/compiler/lib/src/js_backend/no_such_method_registry.dart
@@ -59,6 +59,8 @@ class NoSuchMethodRegistry {
       : this._backend = backend,
         this._compiler = backend.compiler;
 
+  DiagnosticReporter get reporter => _compiler.reporter;
+
   bool get hasThrowingNoSuchMethod => throwingImpls.isNotEmpty;
   bool get hasComplexNoSuchMethod => otherImpls.isNotEmpty;
 
@@ -82,19 +84,19 @@ class NoSuchMethodRegistry {
   void emitDiagnostic() {
     throwingImpls.forEach((e) {
         if (!_hasForwardingSyntax(e)) {
-          _compiler.reportHintMessage(
+          reporter.reportHintMessage(
               e, MessageKind.DIRECTLY_THROWING_NSM);
         }
       });
     complexNoReturnImpls.forEach((e) {
         if (!_hasForwardingSyntax(e)) {
-          _compiler.reportHintMessage(
+          reporter.reportHintMessage(
               e, MessageKind.COMPLEX_THROWING_NSM);
         }
       });
     complexReturningImpls.forEach((e) {
         if (!_hasForwardingSyntax(e)) {
-          _compiler.reportHintMessage(
+          reporter.reportHintMessage(
               e, MessageKind.COMPLEX_RETURNING_NSM);
         }
       });