Resynthesize constructor initializers from Kernel.

runtime/vm/kernel_binary_flowgraph.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/kernel_binary_flowgraph.h"
 
 #include "vm/compiler.h"
 #include "vm/longjump.h"
 #include "vm/object_store.h"
 
@@ skipping 421 matching lines @@
           scope_->LookupVariable(Symbols::AsyncStackTraceVar(), true);
       if (temp != NULL) {
         scope_->CaptureVariable(temp);
       }
     }
   }
 }
 
 void StreamingScopeBuilder::VisitInitializer() {
   Tag tag = builder_->ReadTag();
+  builder_->ReadByte();  // read isSynthetic flag.
   switch (tag) {
     case kInvalidInitializer:
       return;
     case kFieldInitializer:
       builder_->SkipCanonicalNameReference();  // read field_reference.
       VisitExpression();                       // read value.
       return;
     case kSuperInitializer:
       builder_->SkipCanonicalNameReference();  // read target_reference.
       VisitArguments();                        // read arguments.
@@ skipping 2391 matching lines @@
   //   class A {
   //     var x;
   //     var y;
   //     A(this.x) : super(expr), y = (expr);
   //   }
   {
     AlternativeReadingScope alt(reader_, initializers_offset);
     intptr_t list_length = ReadListLength();  // read initializers list length.
     for (intptr_t i = 0; i < list_length; ++i) {
       Tag tag = ReadTag();
+      ReadByte();  // read isSynthetic flag.
       switch (tag) {
         case kInvalidInitializer:
           UNIMPLEMENTED();
           return Fragment();
         case kFieldInitializer: {
           NameIndex canonical_name =
               ReadCanonicalNameReference();  // read field_reference.
           instructions += BuildFieldInitializer(canonical_name);  // read value.
           break;
         }
@@ skipping 4406 matching lines @@
     }
   }
 
   return Array::Handle(Array::null());
 }
 
 }  // namespace kernel
 }  // namespace dart
 
 #endif  // !defined(DART_PRECOMPILED_RUNTIME)