"No SDK, No Problem!" (take 2)

compiler/java/com/google/dart/compiler/PackageLibraryManager.java

Index: compiler/java/com/google/dart/compiler/PackageLibraryManager.java
===================================================================
--- compiler/java/com/google/dart/compiler/PackageLibraryManager.java	(revision 12608)
+++ compiler/java/com/google/dart/compiler/PackageLibraryManager.java	(working copy)
@@ -87,13 +87,21 @@
   }
 
   public PackageLibraryManager(File sdkPath, String platformName) {
+    initLibraryManager(sdkPath);
+    setPackageRoots(DEFAULT_PACKAGE_ROOTS);
+  }
+
+  /**
+   * Initialize the SDK system library manager.
+   * 
+   * @param sdkPath the path to the SDK
+   */
+  protected void initLibraryManager(File sdkPath) {
     if (SDK_LIBRARY_MANAGER == null){
       SDK_LIBRARY_MANAGER = new SystemLibraryManager(sdkPath);
     }
-    setPackageRoots(DEFAULT_PACKAGE_ROOTS);
   }
 
-
   /**
    * Expand a relative or short URI (e.g. "dart:html") which is implementation independent to its
    * full URI (e.g. "dart://html/com/google/dart/htmllib/html.dart").