Move common URIs to common/names.dart

pkg/compiler/lib/src/dart_backend/renamer.dart

Index: pkg/compiler/lib/src/dart_backend/renamer.dart
diff --git a/pkg/compiler/lib/src/dart_backend/renamer.dart b/pkg/compiler/lib/src/dart_backend/renamer.dart
index f13af6fa8724d09a8c0afb535d22efef9ac16fea..02f93656879558080de4c92e0d035d503a1e3de1 100644
--- a/pkg/compiler/lib/src/dart_backend/renamer.dart
+++ b/pkg/compiler/lib/src/dart_backend/renamer.dart
@@ -146,7 +146,7 @@ class PlaceholderRenamer {
       }
       if (library.isPlatformLibrary) {
         // TODO(johnniwinther): Handle prefixes for dart:core.
-        if (library.canonicalUri == Compiler.DART_CORE) return entity.name;
+        if (library.canonicalUri == Uris.dart_core) return entity.name;
         if (library.isInternalLibrary) {
           throw new SpannableAssertionFailure(entity,
               "Internal library $library should never have been imported from "