Update scan, changed and discard to handle "packages" and "pubspec.yaml"

editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/analysis/EverythingChangedTask.java

 /*
  * Copyright 2012 Dart project authors.
  * 
  * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
  * in compliance with the License. You may obtain a copy of the License at
  * 
  * http://www.eclipse.org/legal/epl-v10.html
  * 
  * Unless required by applicable law or agreed to in writing, software distributed under the License
  * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
  * or implied. See the License for the specific language governing permissions and limitations under
  * the License.
  */
 package com.google.dart.tools.core.analysis;
 
 class EverythingChangedTask extends Task {
 
   private final AnalysisServer server;
-  private final Context context;
 
-  EverythingChangedTask(AnalysisServer server, Context context) {
+  EverythingChangedTask(AnalysisServer server) {
     this.server = server;
-    this.context = context;
   }
 
   @Override
   public boolean isBackgroundAnalysis() {
     return false;
   }
 
   @Override
   public boolean isPriority() {
     return true;
   }
 
   @Override
   public void perform() {
-    context.discardLibraries();
+    server.getSavedContext().discardAllLibraries();
     server.queueAnalyzeContext();
   }
 }