Use a single file for app snapshots.

runtime/vm/clustered_snapshot.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/clustered_snapshot.h"
 
 #include "platform/assert.h"
 #include "vm/bootstrap.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
@@ skipping 5270 matching lines @@
   if (vm_isolate_snapshot_buffer() != NULL) {
     num_base_objects = WriteVmIsolateSnapshot();
     ASSERT(num_base_objects != 0);
   } else {
     num_base_objects = 0;
   }
 
   WriteIsolateFullSnapshot(num_base_objects);
 
   if (Snapshot::IncludesCode(kind_)) {
-    instructions_writer_->Write();
+    instructions_writer_->Write(*vm_isolate_snapshot_buffer_,
+                                vm_isolate_snapshot_size_,
+                                *isolate_snapshot_buffer_,
+                                isolate_snapshot_size_);
 
     OS::Print("VMIsolate(CodeSize): %" Pd "\n", VmIsolateSnapshotSize());
     OS::Print("Isolate(CodeSize): %" Pd "\n", IsolateSnapshotSize());
     OS::Print("ReadOnlyData(CodeSize): %" Pd "\n",
               instructions_writer_->data_size());
     OS::Print("Instructions(CodeSize): %" Pd "\n",
               instructions_writer_->text_size());
     intptr_t total = VmIsolateSnapshotSize() +
                      IsolateSnapshotSize() +
                      instructions_writer_->data_size() +
@@ skipping 37 matching lines @@
 
   deserializer.ReadVMSnapshot();
 
   Dart::set_instructions_snapshot_buffer(instructions_buffer_);
   Dart::set_data_snapshot_buffer(data_buffer_);
 
   return ApiError::null();
 }
 
 }  // namespace dart