Fix most implementations of UriResolver.restoreAbsolute.

pkg/analyzer/lib/src/generated/source.dart

Index: pkg/analyzer/lib/src/generated/source.dart
diff --git a/pkg/analyzer/lib/src/generated/source.dart b/pkg/analyzer/lib/src/generated/source.dart
index 14b2d81996619c13cdf3bba4a6f1bbc36ad06cd9..e6d7a542688203ee0b2dae23e83eb7538ff5fc60 100644
--- a/pkg/analyzer/lib/src/generated/source.dart
+++ b/pkg/analyzer/lib/src/generated/source.dart
@@ -1073,11 +1073,10 @@ abstract class UriResolver {
   Source resolveAbsolute(Uri uri, [Uri actualUri]);
 
   /**
-   * Return an absolute URI that represents the given source, or `null` if a valid URI cannot
-   * be computed.
+   * Return an absolute URI that represents the given [source], or `null` if a
+   * valid URI cannot be computed.
    *
-   * @param source the source to get URI for
-   * @return the absolute URI representing the given source
+   * The computation should be based solely on [source.fullName].
    */
   Uri restoreAbsolute(Source source) => null;
 }