Fix a URI related problem on windows.

editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/model/DartLibraryImpl.java

 /*
  * Copyright (c) 2011, the 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
@@ skipping 93 matching lines @@
   /**
    * Answer a library source for the specified file
    * 
    * @param libraryFile the *.dart library configuration file
    * @return the source file or <code>null</code> if it could not be determined
    */
   private static LibrarySource newLibrarySourceFile(File libraryFile) throws AssertionError {
     if (libraryFile == null) {
       return null;
     }
-    URI uri;
-    try {
-      // We need to use the 3-arg constructor of URI in order to properly escape file system chars.
-      uri = new URI("file", libraryFile.getPath(), null);
-    } catch (URISyntaxException e) {
-      throw new AssertionError(e);
-    }
+
+    URI uri = libraryFile.toURI().normalize();
+
     SystemLibraryManager libMgr = SystemLibraryManagerProvider.getSystemLibraryManager();
+
     return new UrlLibrarySource(uri, libMgr);
   }
 
   /**
    * Answer a library source for the specified file
    * 
    * @param libraryFile the *.dart library configuration file
    * @return the source file or <code>null</code> if it could not be determined
    */
   private static LibrarySource newLibrarySourceFile(IFile libraryFile) {
@@ skipping 717 matching lines @@
         return DartCompilerUtilities.parseSource(libraryFile.getName(),
             IFileUtilities.getContents(libraryFile), null);
       }
     } catch (Exception exception) {
       DartCore.logError("Could not read and parse a library file", exception);
       // Fall through to return null.
     }
     return null;
   }
 }