Use entities in various ssa helpers.

pkg/compiler/lib/src/ssa/optimize.dart

Index: pkg/compiler/lib/src/ssa/optimize.dart
diff --git a/pkg/compiler/lib/src/ssa/optimize.dart b/pkg/compiler/lib/src/ssa/optimize.dart
index 428bb4117f83092b8b77fdae0e1a668d56fceb2f..467ab7f2440b20a15a3edd23c4e00fa67fe6a810 100644
--- a/pkg/compiler/lib/src/ssa/optimize.dart
+++ b/pkg/compiler/lib/src/ssa/optimize.dart
@@ -101,8 +101,8 @@ class SsaOptimizerTask extends CompilerTask {
       // Simplifying interceptors is not strictly just an optimization, it is
       // required for implementation correctness because the code generator
       // assumes it is always performed.
-      runPhase(
-          new SsaSimplifyInterceptors(compiler, closedWorld, work.element));
+      runPhase(new SsaSimplifyInterceptors(
+          compiler, closedWorld, work.element.enclosingClass));
 
       SsaDeadCodeEliminator dce = new SsaDeadCodeEliminator(closedWorld, this);
       runPhase(dce);
@@ -115,7 +115,8 @@ class SsaOptimizerTask extends CompilerTask {
           new SsaInstructionSimplifier(backend, closedWorld, this, registry),
           new SsaCheckInserter(
               trustPrimitives, backend, closedWorld, boundsChecked),
-          new SsaSimplifyInterceptors(compiler, closedWorld, work.element),
+          new SsaSimplifyInterceptors(
+              compiler, closedWorld, work.element.enclosingClass),
           new SsaDeadCodeEliminator(closedWorld, this),
         ];
       } else {