Cleanup 1: split parts into their own libraries, remove unused imports

pkg/compiler/lib/src/native/native.dart

Index: pkg/compiler/lib/src/native/native.dart
diff --git a/pkg/compiler/lib/src/native/native.dart b/pkg/compiler/lib/src/native/native.dart
index 487832b6c11060ac2613e30fd15a665d1fff60e7..4a1a641f6ee6e8668dc1c0189698ca936e5aac96 100644
--- a/pkg/compiler/lib/src/native/native.dart
+++ b/pkg/compiler/lib/src/native/native.dart
@@ -4,59 +4,14 @@
 
 library native;
 
-import 'dart:collection' show Queue;
-
-import '../common.dart';
-import '../common/backend_api.dart' show
-    ForeignResolver;
-import '../common/registry.dart' show
-    Registry;
-import '../common/resolution.dart' show
-    Parsing,
-    Resolution;
-import '../compiler.dart' show
-    Compiler;
-import '../constants/values.dart';
-import '../core_types.dart' show
-    CoreTypes;
-import '../dart_types.dart';
-import '../enqueue.dart' show
-    Enqueuer,
-    ResolutionEnqueuer;
+import '../compiler.dart' show Compiler;
 import '../elements/elements.dart';
-import '../elements/modelx.dart' show
-    BaseClassElementX,
-    ElementX,
-    FunctionElementX,
-    LibraryElementX;
-import '../js/js.dart' as js;
-import '../js_backend/backend_helpers.dart' show
-    BackendHelpers;
-import '../js_backend/js_backend.dart';
-import '../js_emitter/js_emitter.dart' show
-    CodeEmitterTask,
-    NativeEmitter;
-import '../parser/listener.dart' show
-    Listener;
-import '../parser/element_listener.dart' show
-    ElementListener;
-import '../ssa/ssa.dart';
-import '../tokens/token.dart' show
-    BeginGroupToken,
-    Token;
-import '../tokens/token_constants.dart' as Tokens show
-    EOF_TOKEN,
-    STRING_TOKEN;
-import '../tree/tree.dart';
-import '../universe/side_effects.dart' show
-    SideEffects;
-import '../util/util.dart';
 
-part 'behavior.dart';
-part 'enqueue.dart';
-part 'js.dart';
-part 'scanner.dart';
-part 'ssa.dart';
+export 'behavior.dart';
+export 'enqueue.dart';
+export 'js.dart';
+export 'scanner.dart';
+export 'ssa.dart';
 
 bool maybeEnableNative(Compiler compiler,
                        LibraryElement library) {