Do the null deref guard before doing inlining, especially before doing type checks on the parameter…

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

Index: sdk/lib/_internal/compiler/implementation/ssa/builder.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/ssa/builder.dart	(revision 22983)
+++ sdk/lib/_internal/compiler/implementation/ssa/builder.dart	(working copy)
@@ -1320,16 +1320,16 @@
     }
 
     assert(canBeInlined);
-    InliningState state = enterInlinedMethod(
-        function, selector, argumentsNodes, providedArguments, currentNode);
-    // Add an explicit null check on the receiver. We use [element]
-    // to get the same name in the NoSuchMethodError message as if we had
-    // called it.
+    // Add an explicit null check on the receiver before doing the
+    // inlining. We use [element] to get the same name in the NoSuchMethodError
+    // message as if we had called it.
     if (element.isInstanceMember()
         && (selector.mask == null || selector.mask.isNullable)) {
       addWithPosition(
           new HFieldGet(element, providedArguments[0]), currentNode);
     }
+    InliningState state = enterInlinedMethod(
+        function, selector, argumentsNodes, providedArguments, currentNode);
     inlinedFrom(element, () {
       functionExpression.body.accept(this);
     });