Revert "Move dart2js from sdk/lib/_internal/compiler to pkg/compiler"

site/try/poi/poi.dart

 // Copyright (c) 2014, 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.
 
 library trydart.poi;
 
 import 'dart:async' show
     Completer,
     Future;
 
 import 'dart:io' as io;
 
 import 'dart:convert' show
     UTF8;
 
 import 'package:dart2js_incremental/dart2js_incremental.dart' show
     reuseCompiler;
 
 import 'package:dart2js_incremental/library_updater.dart' show
     LibraryUpdater;
 
-import 'package:compiler/src/source_file_provider.dart' show
+import 'package:compiler/implementation/source_file_provider.dart' show
     FormattingDiagnosticHandler;
 
 import 'package:compiler/compiler.dart' as api;
 
-import 'package:compiler/src/dart2jslib.dart' show
+import 'package:compiler/implementation/dart2jslib.dart' show
     Compiler,
     CompilerTask,
     Enqueuer,
     QueueFilter,
     WorkItem;
 
-import 'package:compiler/src/elements/visitor.dart' show
+import 'package:compiler/implementation/elements/visitor.dart' show
     ElementVisitor;
 
-import 'package:compiler/src/elements/elements.dart' show
+import 'package:compiler/implementation/elements/elements.dart' show
     AbstractFieldElement,
     ClassElement,
     CompilationUnitElement,
     Element,
     ElementCategory,
     FunctionElement,
     LibraryElement,
     ScopeContainerElement;
 
-import 'package:compiler/src/elements/modelx.dart' as modelx;
+import 'package:compiler/implementation/elements/modelx.dart' as modelx;
 
-import 'package:compiler/src/elements/modelx.dart' show
+import 'package:compiler/implementation/elements/modelx.dart' show
     DeclarationSite;
 
-import 'package:compiler/src/dart_types.dart' show
+import 'package:compiler/implementation/dart_types.dart' show
     DartType;
 
-import 'package:compiler/src/scanner/scannerlib.dart' show
+import 'package:compiler/implementation/scanner/scannerlib.dart' show
     EOF_TOKEN,
     IDENTIFIER_TOKEN,
     KEYWORD_TOKEN,
     PartialClassElement,
     PartialElement,
     Token;
 
-import 'package:compiler/src/js/js.dart' show
+import 'package:compiler/implementation/js/js.dart' show
     js;
 
 /// Enabled by the option --enable-dart-mind.  Controls if this program should
 /// be querying Dart Mind.
 bool isDartMindEnabled = false;
 
 /// Iterator over lines from standard input (or the argument array).
 Iterator<String> stdin;
 
 /// Enabled by the option --simulate-mutation. When true, this program will
@@ skipping 709 matching lines @@
 
 modelx.ImportScope importScope(modelx.LibraryElementX element) {
   return element.importScope;
 }
 
 class PoiTask extends CompilerTask {
   PoiTask(Compiler compiler) : super(compiler);
 
   String get name => 'POI';
 }