Use a common subroutine for the snapshot reading and writing of strings.

runtime/vm/object.h

 // Copyright (c) 2011, 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_H_
 #define VM_OBJECT_H_
 
 #include "vm/assert.h"
 #include "vm/dart.h"
 #include "vm/globals.h"
@@ skipping 2471 matching lines @@
     // heap allocation.
     raw_ptr()->length_ = Smi::New(value);
   }
 
   void SetHash(intptr_t value) const {
     // This is only safe because we create a new Smi, which does not cause
     // heap allocation.
     raw_ptr()->hash_ = Smi::New(value);
   }
 
+  template<typename HandleType, typename ElementType>
+  static RawString* ReadFromImpl(SnapshotReader* reader,
+                                 intptr_t object_id,
+                                 bool classes_serialized);
+
   HEAP_OBJECT_IMPLEMENTATION(String, Instance);
 };
 
 
 class OneByteString : public String {
  public:
   virtual int32_t CharAt(intptr_t index) const {
     return *CharAddr(index);
   }
 
@@ skipping 487 matching lines @@
 }
 
 
 void Context::SetAt(intptr_t index, const Instance& value) const {
   StorePointer(InstanceAddr(index), value.raw());
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_