Implement DeclarationMirror.location for all but ParameterMirrors.

tests/lib/mirrors/method_mirror_location_test.dart

 // Copyright (c) 2014, 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 test.method_location;
 
 import "dart:mirrors";
 import "package:expect/expect.dart";
 
 part 'method_mirror_location_other.dart';
@@ skipping 15 matching lines @@
   Expect.equals(column, methodMirror.location.column, "column");
 }
 
 class ClassInMainFile {
 
   ClassInMainFile();
 
   method() {}
 }
 
-topLevelInMainFile() {}
+void topLevelInMainFile() {}
   spaceIdentedInMainFile() {}
         tabIdentedInMainFile() {}
 
 class HasImplicitConstructor {}
 
 typedef bool Predicate(num n);
 
 main() {
   localFunction(x) { return x; }
 
@@ skipping 17 matching lines @@
                  otherSuffix, 11, 3);
   expectLocation(reflect(topLevelInOtherFile), otherSuffix, 14, 1);
   expectLocation(reflect(spaceIdentedInOtherFile), otherSuffix, 16, 3);
   expectLocation(reflect(tabIdentedInOtherFile), otherSuffix, 18, 2);
 
   // Synthetic methods.
   Expect.isNull(reflectClass(HasImplicitConstructor)
                 .declarations[#HasImplicitConstructor].location);
   Expect.isNull((reflectType(Predicate) as TypedefMirror).referent.callMethod.location);
 }