Revert "Remove Registry from registerMetadataConstant" and "Serialize metadata"

pkg/compiler/lib/src/elements/modelx.dart

Index: pkg/compiler/lib/src/elements/modelx.dart
diff --git a/pkg/compiler/lib/src/elements/modelx.dart b/pkg/compiler/lib/src/elements/modelx.dart
index 248a9ef96606a9833d5128969d8c265cd8d6ab90..e1fd27102310ec9002e5d4ff473bbbf8dd42fda3 100644
--- a/pkg/compiler/lib/src/elements/modelx.dart
+++ b/pkg/compiler/lib/src/elements/modelx.dart
@@ -3193,8 +3193,6 @@ abstract class MetadataAnnotationX implements MetadataAnnotation {
    */
   Token get beginToken;
 
-  Token get endToken;
-
   MetadataAnnotationX([this.resolutionState = STATE_NOT_STARTED]);
 
   MetadataAnnotation ensureResolved(Resolution resolution) {
@@ -3210,11 +3208,6 @@ abstract class MetadataAnnotationX implements MetadataAnnotation {
 
   Node parseNode(ParsingContext parsing);
 
-  SourceSpan get sourcePosition {
-    Uri uri = annotatedElement.compilationUnit.script.resourceUri;
-    return new SourceSpan.fromTokens(uri, beginToken, endToken);
-  }
-
   String toString() => 'MetadataAnnotation($constant, $resolutionState)';
 }