Revert "Dummy receiver optimization"

sdk/lib/_internal/compiler/implementation/ssa/interceptor_simplifier.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/interceptor_simplifier.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/interceptor_simplifier.dart b/sdk/lib/_internal/compiler/implementation/ssa/interceptor_simplifier.dart
index fcc8fec7d013a2137a3f566f700b80df001d5891..e4a4ad825268f78016408b3c07a567ed5a23077c 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/interceptor_simplifier.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/interceptor_simplifier.dart
@@ -186,7 +186,7 @@ class SsaSimplifyInterceptors extends HBaseVisitor
       if (interceptedClasses.contains(backend.jsNumberClass)
           && !(interceptedClasses.contains(backend.jsDoubleClass)
                || interceptedClasses.contains(backend.jsIntClass))) {
-        for (HInstruction user in node.usedBy) {
+        for (var user in node.usedBy) {
           if (user is! HInvoke) continue;
           Set<ClassElement> intercepted =
               backend.getInterceptedClassesOn(user.selector.name);
@@ -200,7 +200,7 @@ class SsaSimplifyInterceptors extends HBaseVisitor
       }
     } else {
       interceptedClasses = new Set<ClassElement>();
-      for (HInstruction user in node.usedBy) {
+      for (var user in node.usedBy) {
         if (user is HIs) {
           // Is-checks can be performed on any intercepted class.
           interceptedClasses.addAll(backend.interceptedClasses);
@@ -215,29 +215,7 @@ class SsaSimplifyInterceptors extends HBaseVisitor
 
     HInstruction receiver = node.receiver;
     if (canUseSelfForInterceptor(receiver, interceptedClasses)) {
-      List<HInstruction> users = node.usedBy.toList();
       node.block.rewrite(node, receiver);
-
-      // Replace occurences of the receiver in invocations with a dummy receiver
-      // if the selector matches only methods that ignore the receiver.
-      JavaScriptBackend backend = compiler.backend;
-      for (HInstruction user in users) {
-        if (user is HInvokeDynamic) {
-          HInvokeDynamic invoke = user;
-          if (invoke.getDartReceiver(compiler) == receiver
-              && !backend.isInterceptedMixinSelector(invoke.selector)) {
-            // [receiver] might not be the direct input since `node.receiver`
-            // looks through type conversion nodes like [TypeKnown].
-            HInstruction immediateReceiver = invoke.inputs[1];
-            Constant constant = new DummyReceiverConstant(
-                immediateReceiver.instructionType);
-            HConstant dummy = graph.addConstant(constant, compiler);
-            immediateReceiver.usedBy.remove(invoke);
-            invoke.inputs[1] = dummy;
-            dummy.usedBy.add(invoke);
-          }
-        }
-      }
       return false;
     }