Improve the mirror support for deferred loading.

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

Index: sdk/lib/_internal/compiler/implementation/deferred_load.dart
diff --git a/sdk/lib/_internal/compiler/implementation/deferred_load.dart b/sdk/lib/_internal/compiler/implementation/deferred_load.dart
index 298c7204bec55f56319c2b2e547f2051b9386842..8585c4825134d354927f55558c5f9eff19717d6f 100644
--- a/sdk/lib/_internal/compiler/implementation/deferred_load.dart
+++ b/sdk/lib/_internal/compiler/implementation/deferred_load.dart
@@ -303,7 +303,7 @@ class DeferredLoadTask extends CompilerTask {
   void _collectAllElementsAndConstantsResolvedFrom(Element element,
       Set<Element> elements,
       Set<Constant> constants) {
-    element = element.implementation;
+    // TODO(sigurdm): How is metadata on a patch-class handled?
     for (MetadataAnnotation metadata in element.metadata) {
       if (metadata.value != null) {
         constants.add(metadata.value);
@@ -442,10 +442,26 @@ class DeferredLoadTask extends CompilerTask {
           // things to the output units for the library.
           List<MirrorUsage> mirrorUsages = mirrorsResult[library];
           if (mirrorUsages == null) continue;
+
+          void mapDependenciesIfResolved(Element element) {
+            // If there is a target for this class, but no use of mirrors the
+            // class will not be resolved. We just skip it.
+            if (element is ClassElement &&
+                !(element as ClassElement).isResolved) {
+              return;
+            }
+            _mapDependencies(element, deferredImport);
+          }
+
           for (MirrorUsage usage in mirrorUsages) {
             if (usage.targets != null) {
               for (Element dependency in usage.targets) {
-                _mapDependencies(dependency, deferredImport);
+                if (dependency.isLibrary()) {
+                  LibraryElement library = dependency;
+                  library.forEachLocalMember(mapDependenciesIfResolved);
+                } else {
+                  mapDependenciesIfResolved(dependency);
+                }
               }
             }
             if (usage.metaTargets != null) {
@@ -484,10 +500,14 @@ class DeferredLoadTask extends CompilerTask {
             }
           }
           if (usesMirrors) {
-            for (Link link in compiler.enqueuer.allElementsByName.values) {
-              for (Element dependency in link) {
-                _mapDependencies(dependency, deferredImport);
-              }
+            // Add all resolved elements to the output unit.
+            for (Element element in
+                compiler.enqueuer.resolution.resolvedElements.keys) {
+              _mapDependencies(element, deferredImport);
+            }
+            for (Element element in
+                compiler.mirrorDependencies.otherDependencies) {
+              _mapDependencies(element, deferredImport);
             }
           }
         }