Deal better with missing sources in code_transformers and polymer

pkg/code_transformers/lib/src/resolver_impl.dart

Index: pkg/code_transformers/lib/src/resolver_impl.dart
diff --git a/pkg/code_transformers/lib/src/resolver_impl.dart b/pkg/code_transformers/lib/src/resolver_impl.dart
index ad73da401ae44cc2fc5e5ee674626b26234b44e1..c6be747d03ebcb7d2257b37579b6fe141fd95f63 100644
--- a/pkg/code_transformers/lib/src/resolver_impl.dart
+++ b/pkg/code_transformers/lib/src/resolver_impl.dart
@@ -136,6 +136,8 @@ class ResolverImpl implements Resolver {
           _context.applyChanges(
               new ChangeSet()..removedSource(source));
           sources[assetId].updateContents(null);
+        } else if (source == null) {
+          transform.logger.warning('Asset not found: $assetId');

[Siggi Cherem (dart-lang), 2014/04/10 20:05:47]

we already compute the span inside dependentsAssets below, so one option would
be to pass that through. If you think it's worth it, I'm happy to add that.

         }
       }));
     }
@@ -159,8 +161,11 @@ class ResolverImpl implements Resolver {
       _context.applyChanges(changeSet);
       // Force resolve each entry point (the getter will ensure the library is
       // computed first).
-      _entryLibraries = entryPoints
-          .map((id) => _context.computeLibraryElement(sources[id])).toList();
+      _entryLibraries = entryPoints.map((id) {
+        var source = sources[id];
+        if (source == null) return null;
+        return _context.computeLibraryElement(source);
+      }).toList();
     });
   }