Find diagnostic locations for use in new compiler API.

dart/frog/leg/apiimpl.dart

Index: dart/frog/leg/apiimpl.dart
diff --git a/dart/frog/leg/apiimpl.dart b/dart/frog/leg/apiimpl.dart
index 6b29e5c4b9f4c20bf16c8ad077525db1025166c9..0c9e02031fddab2522f9dcbf6058a9fcf4a3fb21 100644
--- a/dart/frog/leg/apiimpl.dart
+++ b/dart/frog/leg/apiimpl.dart
@@ -22,10 +22,6 @@ class Compiler extends leg.Compiler {
     return library;
   }
 
-  void log(message) {
-    handler(null, null, null, message, false);
-  }
-
   Script readScript(Uri uri, [ScriptTag node]) {
     String uriName = uri.toString();
     // TODO(ahe): Clean this up.
@@ -55,4 +51,12 @@ class Compiler extends leg.Compiler {
     }
     return success;
   }
+
+  void reportDiagnostic(leg.SourceSpan span, String message, bool fatal) {
+    if (span === null) {
+      handler(null, null, null, message, fatal);
+    } else {
+      handler(span.uri, span.begin, span.end, message, fatal);
+    }
+  }
 }