Revert "Move Compiler.libraries to LibraryLoder."

tests/compiler/dart2js/deferred_mirrors_test.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.
 
 // Test of the graph segmentation algorithm used by deferred loading
 // to determine which elements can be deferred and which libraries
 // much be included in the initial download (loaded eagerly).
 
 import 'package:expect/expect.dart';
 import "package:async_helper/async_helper.dart";
 import 'memory_source_file_helper.dart';
 import "memory_compiler.dart";
 
 import 'package:compiler/implementation/dart2jslib.dart'
        as dart2js;
 
 runTest(String mainScript, test) {
   Compiler compiler = compilerFor(MEMORY_SOURCE_FILES,
       outputProvider: new OutputCollector());
   asyncTest(() => compiler.run(Uri.parse(mainScript))
       .then((_) => test(compiler)));
 }
 
-lookupLibrary(compiler, name) {
-  return compiler.libraryLoader.lookupLibrary(Uri.parse(name));
-}
-
 void main() {
   runTest('memory:main.dart', (compiler) {
     var main = compiler.mainApp.find(dart2js.Compiler.MAIN);
     Expect.isNotNull(main, "Could not find 'main'");
     compiler.deferredLoadTask.onResolutionComplete(main);
     var outputUnitForElement = compiler.deferredLoadTask.outputUnitForElement;
 
-    var lib1 = lookupLibrary(compiler, "memory:lib1.dart");
-    var lib2 = lookupLibrary(compiler, "memory:lib2.dart");
-    var mathLib = lookupLibrary(compiler, "dart:math");
+    var lib1 = compiler.libraries["memory:lib1.dart"];
+    var lib2 = compiler.libraries["memory:lib2.dart"];
+    var mathLib = compiler.libraries["dart:math"];
     var sin = mathLib.find('sin');
     var foo1 = lib1.find("foo1");
     var foo2 = lib2.find("foo2");
     var field2 = lib2.find("field2");
 
     Expect.notEquals(outputUnitForElement(main), outputUnitForElement(foo1));
     Expect.equals(outputUnitForElement(main), outputUnitForElement(sin));
     Expect.equals(outputUnitForElement(foo2), outputUnitForElement(field2));
   });
   runTest('memory:main2.dart', (compiler) {
     // Just check that the compile runs.
     // This is a regression test.
     Expect.isTrue(true);
   });
   runTest('memory:main3.dart', (compiler) {
     var main = compiler.mainApp.find(dart2js.Compiler.MAIN);
     Expect.isNotNull(main, "Could not find 'main'");
     compiler.deferredLoadTask.onResolutionComplete(main);
     var outputUnitForElement = compiler.deferredLoadTask.outputUnitForElement;
 
-    var mainLib = lookupLibrary(compiler, "memory:main3.dart");
-    var lib3 = lookupLibrary(compiler, "memory:lib3.dart");
+    var mainLib = compiler.libraries["memory:main3.dart"];
+    var lib3 = compiler.libraries["memory:lib3.dart"];
     var C = mainLib.find("C");
     var foo = lib3.find("foo");
 
     Expect.notEquals(outputUnitForElement(main), outputUnitForElement(foo));
     Expect.equals(outputUnitForElement(main), outputUnitForElement(C));
   });
   runTest('memory:main4.dart', (compiler) {
     var main = compiler.mainApp.find(dart2js.Compiler.MAIN);
     Expect.isNotNull(main, "Could not find 'main'");
     compiler.deferredLoadTask.onResolutionComplete(main);
     var outputUnitForElement = compiler.deferredLoadTask.outputUnitForElement;
 
-    var mainLib = lookupLibrary(compiler, "memory:main4.dart");
-    var lib4 = lookupLibrary(compiler, "memory:lib4.dart");
-    var lib5 = lookupLibrary(compiler, "memory:lib5.dart");
-    var lib6 = lookupLibrary(compiler, "memory:lib6.dart");
+    var mainLib = compiler.libraries["memory:main4.dart"];
+    var lib4 = compiler.libraries["memory:lib4.dart"];
+    var lib5 = compiler.libraries["memory:lib5.dart"];
+    var lib6 = compiler.libraries["memory:lib6.dart"];
     var foo5 = lib5.find("foo");
     var foo6 = lib6.find("foo");
 
     Expect.notEquals(outputUnitForElement(main), outputUnitForElement(foo5));
     Expect.equals(outputUnitForElement(foo5), outputUnitForElement(foo6));
   });
 }
 
 // "lib1.dart" uses mirrors without a MirrorsUsed annotation, so everything
 // should be put in the "lib1" output unit.
@@ skipping 103 matching lines @@
 library lib5;
 
 foo() {}
 """,
 "lib6.dart": """
 library lib6;
 
 foo() {}
 """,
 };