robolectric/src/main/java/org/robolectric/ApkLoader.java
@Nonnull
  synchronized public PackageResourceTable getCompileTimeSdkResourceTable() {
    if (compiletimeSdkResourceTable == null) {
      ResourceTableFactory resourceTableFactory = new ResourceTableFactory();
      compiletimeSdkResourceTable = resourceTableFactory
          .newFrameworkResourceTable(new ResourcePath(android.R.class, null, null));
    }
    return compiletimeSdkResourceTable;
  }
@Nonnull
  synchronized public PackageResourceTable getCompileTimeSdkResourceTable() {
    if (compiletimeSdkResourceTable == null) {
      ResourceTableFactory resourceTableFactory = new ResourceTableFactory();
      compiletimeSdkResourceTable = resourceTableFactory
          .newFrameworkResourceTable(new ResourcePath(android.R.class, null, null));
    }
    return compiletimeSdkResourceTable;
  }
Returns the ResourceTable for the compile time SDK.