Support deserialized compilation of the empty program.

pkg/compiler/lib/src/common/resolution.dart

Index: pkg/compiler/lib/src/common/resolution.dart
diff --git a/pkg/compiler/lib/src/common/resolution.dart b/pkg/compiler/lib/src/common/resolution.dart
index 0286376b53d82f6797180edddca9889a74fcf509..998c59bd1636d403fde70d3bbb685ba3bdd86f4e 100644
--- a/pkg/compiler/lib/src/common/resolution.dart
+++ b/pkg/compiler/lib/src/common/resolution.dart
@@ -182,8 +182,18 @@ class ListLiteralUse {
   }
 }
 
+/// Interface for the accessing the front-end analysis.
+// TODO(johnniwinther): Find a better name for this.
+abstract class Frontend {
+  /// Returns the `ResolvedAst` for the [element].
+  ResolvedAst getResolvedAst(Element element);
+
+  /// Returns the [ResolutionImpact] for [element].
+  ResolutionImpact getResolutionImpact(Element element);
+}
+
 // TODO(johnniwinther): Rename to `Resolver` or `ResolverContext`.
-abstract class Resolution {
+abstract class Resolution implements Frontend {
   Parsing get parsing;
   DiagnosticReporter get reporter;
   CoreTypes get coreTypes;