Split js_backend into multiple libraries

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

 // Copyright (c) 2015, 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 js_backend;
+import '../common.dart';
+import '../common/names.dart' show Identifiers, Names, Selectors, Uris;
+import '../compiler.dart' show Compiler;
+import '../elements/elements.dart';
+import '../tree/tree.dart';
+import '../types/types.dart';
+
+import 'backend.dart';
 
 /**
  * Categorizes `noSuchMethod` implementations.
  *
  * If user code includes `noSuchMethod` implementations, type inference is
  * hindered because (for instance) any selector where the type of the
  * receiver is not known all implementations of `noSuchMethod` must be taken
  * into account when inferring the return type.
  *
  * The situation can be ameliorated with some heuristics for disregarding some
@@ skipping 242 matching lines @@
       if (body.statements.nodes.head is ExpressionStatement) {
         ExpressionStatement stmt = body.statements.nodes.head;
         return stmt.expression is Throw;
       }
     }
     return false;
   }
 }
 
 enum NsmCategory { DEFAULT, THROWING, NOT_APPLICABLE, OTHER, }