Last cleanup int -> intptr_t. Also removed a hack.

runtime/vm/store_buffer.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_STORE_BUFFER_H_
 #define VM_STORE_BUFFER_H_
 
 #include "platform/assert.h"
 #include "vm/globals.h"
 
@@ skipping 15 matching lines @@
   StoreBufferBlock* next() const { return next_; }
 
   intptr_t Count() const { return top_; }
 
   RawObject* At(intptr_t i) const {
     ASSERT(i >= 0);
     ASSERT(i < top_);
     return pointers_[i];
   }
 
-  static int top_offset() { return OFFSET_OF(StoreBufferBlock, top_); }
-  static int pointers_offset() {
+  static intptr_t top_offset() { return OFFSET_OF(StoreBufferBlock, top_); }
+  static intptr_t pointers_offset() {
     return OFFSET_OF(StoreBufferBlock, pointers_);
   }
 
  private:
   StoreBufferBlock* next_;
   int32_t top_;
   RawObject* pointers_[kSize];
 
   friend class StoreBuffer;
 
@@ skipping 51 matching lines @@
 
   StoreBufferBlock* blocks_;
   intptr_t full_count_;
 
   DISALLOW_COPY_AND_ASSIGN(StoreBuffer);
 };
 
 }  // namespace dart
 
 #endif  // VM_STORE_BUFFER_H_