Fix compilation failure on Win.

src/heap.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 110 matching lines @@
 GCTracer* Heap::tracer_ = NULL;
 
 int Heap::unflattened_strings_length_ = 0;
 
 int Heap::always_allocate_scope_depth_ = 0;
 int Heap::linear_allocation_scope_depth_ = 0;
 int Heap::contexts_disposed_ = 0;
 
 int Heap::young_survivors_after_last_gc_ = 0;
 int Heap::high_survival_rate_period_length_ = 0;
-int Heap::survival_rate_ = 0;
+double Heap::survival_rate_ = 0;
 Heap::SurvivalRateTrend Heap::previous_survival_rate_trend_ = Heap::STABLE;
 Heap::SurvivalRateTrend Heap::survival_rate_trend_ = Heap::STABLE;
 bool Heap::bumped_old_gen_limits_ = false;
 
 #ifdef DEBUG
 bool Heap::allocation_allowed_ = true;
 
 int Heap::allocation_timeout_ = 0;
 bool Heap::disallow_allocation_failure_ = false;
 #endif  // DEBUG
@@ skipping 4693 matching lines @@
 void ExternalStringTable::TearDown() {
   new_space_strings_.Free();
   old_space_strings_.Free();
 }
 
 
 List<Object*> ExternalStringTable::new_space_strings_;
 List<Object*> ExternalStringTable::old_space_strings_;
 
 } }  // namespace v8::internal