Emit a compile-time error for uninitialized final variables.

sdk/lib/_internal/compiler/implementation/warnings.dart

Index: sdk/lib/_internal/compiler/implementation/warnings.dart
diff --git a/sdk/lib/_internal/compiler/implementation/warnings.dart b/sdk/lib/_internal/compiler/implementation/warnings.dart
index 7d5dcbf30e087af02b5bbb8efdbc1743bac34565..50ce914ef07b967ab523f00d3af0d8fcdc5fd9e4 100644
--- a/sdk/lib/_internal/compiler/implementation/warnings.dart
+++ b/sdk/lib/_internal/compiler/implementation/warnings.dart
@@ -881,6 +881,13 @@ void main() {
   const c; // This constant variable must be initialized.
 }"""]);
 
+  static const MessageKind FINAL_WITHOUT_INITIALIZER = const MessageKind(
+      "Error: A final variable must be initialized.",
+      howToFix: "Try adding an initializer or "
+                "removing the 'final' modifier.",
+      examples: const [
+          "class C { static final field; } main() => C.field;"]);
+
   static const MessageKind MEMBER_USES_CLASS_NAME = const MessageKind(
       "Error: Member variable can't have the same name as the class it is "
       "declared in.",