Use JS backend in serialization_analysis_test

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

Index: pkg/compiler/lib/src/elements/common.dart
diff --git a/pkg/compiler/lib/src/elements/common.dart b/pkg/compiler/lib/src/elements/common.dart
index 1e24ff08b0b3ba5fe1d2e2dddba068f20f334af7..5d5f9e673b1dded81eb95979df4008026cca1415 100644
--- a/pkg/compiler/lib/src/elements/common.dart
+++ b/pkg/compiler/lib/src/elements/common.dart
@@ -123,6 +123,19 @@ abstract class ElementCommon implements Element {
   Element get origin {
     throw new UnsupportedError('origin is not supported on $this');
   }
+
+  @override
+  ClassElement get contextClass {
+    ClassElement cls;
+    for (Element e = this; e != null; e = e.enclosingElement) {
+      if (e.isClass) {
+        // Record [e] instead of returning it directly. We need the last class
+        // in the chain since the first classes might be closure classes.
+        cls = e.declaration;
+      }
+    }
+    return cls;
+  }
 }
 
 abstract class LibraryElementCommon implements LibraryElement {
@@ -331,7 +344,7 @@ abstract class ClassElementCommon implements ClassElement {
         classElement.forEachBackendMember((e) => f(classElement, e));
       }
       if (includeInjectedMembers) {
-        if (classElement.patch != null) {
+        if (classElement.isPatched) {
           classElement.patch.forEachLocalMember((e) {
             if (!e.isPatch) f(classElement, e);
           });