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

pkg/compiler/lib/src/compiler.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.compiler_base;
 
 import 'dart:async' show EventSink, Future;
 
 import '../compiler_new.dart' as api;
 import 'cache_strategy.dart' show CacheStrategy;
@@ skipping 1640 matching lines @@
             currentElement.enclosingClass.isEnumClass) {
           // Enums ASTs are synthesized (and give messed up messages).
           return true;
         }
 
         if (currentElement is AstElement) {
           AstElement astElement = currentElement;
           if (astElement.hasNode) {
             Token from = astElement.node.getBeginToken();
             Token to = astElement.node.getEndToken();
-            if (astElement.metadata.isNotEmpty &&
-                astElement.metadata.first.hasNode) {
-              from = astElement.metadata.first.node.getBeginToken();
+            if (astElement.metadata.isNotEmpty) {
+              from = astElement.metadata.first.beginToken;
             }
             return validateToken(from, to);
           }
         }
         return true;
       }, message: "Invalid current element: $currentElement [$begin,$end]."));
     }
     return new SourceSpan.fromTokens(uri, begin, end);
   }
 
@@ skipping 60 matching lines @@
       return spanFromNode(node);
     } else if (node is TokenPair) {
       return spanFromTokens(node.begin, node.end);
     } else if (node is Token) {
       return spanFromTokens(node, node);
     } else if (node is HInstruction) {
       return spanFromHInstruction(node);
     } else if (node is Element) {
       return spanFromElement(node);
     } else if (node is MetadataAnnotation) {
-      return node.sourcePosition;
+      Uri uri = node.annotatedElement.compilationUnit.script.resourceUri;
+      return spanFromTokens(node.beginToken, node.endToken, uri);
     } else if (node is Local) {
       Local local = node;
       return spanFromElement(local.executableContext);
     } else {
       throw 'No error location.';
     }
   }
 
   Element _elementFromHInstruction(HInstruction instruction) {
     return instruction.sourceElement is Element
@@ skipping 346 matching lines @@
   _ElementScanner(this.scanner);
   void scanLibrary(LibraryElement library) => scanner.scanLibrary(library);
   void scanUnit(CompilationUnitElement unit) => scanner.scan(unit);
 }
 
 class _EmptyEnvironment implements Environment {
   const _EmptyEnvironment();
 
   String valueOf(String key) => null;
 }