Adds an assertion to limit snapshot intptr_t size.

runtime/vm/raw_object_snapshot.cc

 // Copyright (c) 2012, 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/bigint_operations.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/snapshot.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
@@ skipping 2363 matching lines @@
 #undef TYPED_DATA_READ
 
 
 RawExternalTypedData* ExternalTypedData::ReadFrom(SnapshotReader* reader,
                                                   intptr_t object_id,
                                                   intptr_t tags,
                                                   Snapshot::Kind kind) {
   ASSERT(kind != Snapshot::kFull);
   intptr_t cid = RawObject::ClassIdTag::decode(tags);
   intptr_t length = reader->ReadSmiValue();
-  uint8_t* data = reinterpret_cast<uint8_t*>(reader->ReadIntptrValue());
+  uint8_t* data = reinterpret_cast<uint8_t*>(reader->ReadRawPointerValue());
   const ExternalTypedData& obj = ExternalTypedData::Handle(
       ExternalTypedData::New(cid, data, length));
-  void* peer = reinterpret_cast<void*>(reader->ReadIntptrValue());
+  void* peer = reinterpret_cast<void*>(reader->ReadRawPointerValue());
   Dart_WeakPersistentHandleFinalizer callback =
       reinterpret_cast<Dart_WeakPersistentHandleFinalizer>(
-          reader->ReadIntptrValue());
+          reader->ReadRawPointerValue());
   obj.AddFinalizer(peer, callback);
   return obj.raw();
 }
 
 
 #define TYPED_DATA_WRITE(type)                                                 \
   {                                                                            \
     type* data = reinterpret_cast<type*>(ptr()->data_);                        \
     for (intptr_t i = 0; i < len; i++) {                                       \
       writer->Write(data[i]);                                                  \
@@ skipping 382 matching lines @@
     // We do not allow objects with native fields in an isolate message.
     writer->SetWriteException(Exceptions::kArgument,
                               "Illegal argument in isolate message"
                               " : (object is a UserTag)");
   } else {
     UNREACHABLE();
   }
 }
 
 }  // namespace dart