Avoid allocating an exception object in the snapshot reader.

runtime/vm/object_store.h

 // 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.
 
 #ifndef VM_OBJECT_STORE_H_
 #define VM_OBJECT_STORE_H_
 
 #include "vm/object.h"
 
 namespace dart {
@@ skipping 362 matching lines @@
   RawInstance* stack_overflow() const { return stack_overflow_; }
   void set_stack_overflow(const Instance& value) {
     stack_overflow_ = value.raw();
   }
 
   RawInstance* out_of_memory() const { return out_of_memory_; }
   void set_out_of_memory(const Instance& value) {
     out_of_memory_ = value.raw();
   }
 
+  RawUnhandledException* preallocated_unhandled_exception() const {
+    return preallocated_unhandled_exception_;
+  }
+  void set_preallocated_unhandled_exception(const UnhandledException& value) {
+    preallocated_unhandled_exception_ = value.raw();
+  }
+
   RawStacktrace* preallocated_stack_trace() const {
     return preallocated_stack_trace_;
   }
   void set_preallocated_stack_trace(const Stacktrace& value) {
     preallocated_stack_trace_ = value.raw();
   }
 
   RawFunction* lookup_port_handler() const {
     return lookup_port_handler_;
   }
@@ skipping 95 matching lines @@
   RawLibrary* profiler_library_;
   RawGrowableObjectArray* libraries_;
   RawGrowableObjectArray* pending_classes_;
   RawGrowableObjectArray* pending_functions_;
   RawGrowableObjectArray* resume_capabilities_;
   RawError* sticky_error_;
   RawString* unhandled_exception_handler_;
   RawContext* empty_context_;
   RawInstance* stack_overflow_;
   RawInstance* out_of_memory_;
+  RawUnhandledException* preallocated_unhandled_exception_;
   RawStacktrace* preallocated_stack_trace_;
   RawFunction* lookup_port_handler_;
   RawFunction* handle_message_function_;
   RawUserTag* default_tag_;
   RawObject** to() {
     return reinterpret_cast<RawObject**>(&handle_message_function_);
   }
 
   friend class SnapshotReader;
 
   DISALLOW_COPY_AND_ASSIGN(ObjectStore);
 };
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_STORE_H_