unfork DDC's copy of most SDK libraries

pkg/dev_compiler/tool/input_sdk/patch/mirrors_patch.dart

 // Copyright (c) 2012, 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.
 
 // Patch library for dart:mirrors.
 
 import 'dart:_js_helper' show patch;
 import 'dart:_js_mirrors' as js;
 
 @patch
 class MirrorSystem {
   @patch
+  LibraryMirror findLibrary(Symbol libraryName) {
+    return libraries.values.singleWhere(
+        (library) => library.simpleName == libraryName);
+  }
+
+  @patch
   static String getName(Symbol symbol) => js.getName(symbol);
 
   @patch
   static Symbol getSymbol(String name, [LibraryMirror library]) {
     return js.getSymbol(name, library);
   }
 }
 
 @patch
 MirrorSystem currentMirrorSystem() => js.currentJsMirrorSystem;
@@ skipping 13 matching lines @@
   return (tm as ClassMirror).originalDeclaration;
 }
 
 @patch
 TypeMirror reflectType(Type key) {
   if (key == dynamic) {
     return currentMirrorSystem().dynamicType;
   }
   return js.reflectType(key);
 }