Assignment expressions in tree IR.

pkg/compiler/lib/src/dart_backend/backend.dart

Index: pkg/compiler/lib/src/dart_backend/backend.dart
diff --git a/pkg/compiler/lib/src/dart_backend/backend.dart b/pkg/compiler/lib/src/dart_backend/backend.dart
index 409b61ffa135e5d58a685a2ef5b0ab683965e633..763e2e3c95f22e7619367b5f662a15414dcef821 100644
--- a/pkg/compiler/lib/src/dart_backend/backend.dart
+++ b/pkg/compiler/lib/src/dart_backend/backend.dart
@@ -182,18 +182,18 @@ class DartBackend extends Backend {
       assert(checkTreeIntegrity(treeRoot));
     }
 
-    applyTreePass(new StatementRewriter());
+    applyTreePass(new StatementRewriter(isDartMode: true));
     applyTreePass(new VariableMerger());
     applyTreePass(new LoopRewriter());
     applyTreePass(new LogicalRewriter());
+    applyTreePass(new PullIntoInitializers());
 
     // Backend-specific transformations.
     new backend_ast_emitter.UnshadowParameters().unshadow(treeRoot);
     context.traceGraph('Unshadow parameters', treeRoot);
 
     TreeElementMapping treeElements = new TreeElementMapping(element);
-    backend_ast.RootNode backendAst =
-        backend_ast_emitter.emit(treeRoot);
+    backend_ast.RootNode backendAst = backend_ast_emitter.emit(treeRoot);
     Node frontend_ast = backend2frontend.emit(treeElements, backendAst);
     return new ElementAst(frontend_ast, treeElements);