Fix the --max-old-space-size flag so it can be used on 64 bit for

src/incremental-marking.cc

 // Copyright 2011 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 24 matching lines @@
 namespace v8 {
 namespace internal {
 
 
 IncrementalMarking::IncrementalMarking(Heap* heap)
     : heap_(heap),
       state_(STOPPED),
       marking_deque_memory_(NULL),
       steps_count_(0),
       steps_took_(0),
+      longest_step_(0.0),
       steps_count_since_last_gc_(0),
       steps_took_since_last_gc_(0),
       should_hurry_(false),
       allocation_marking_factor_(0),
       allocated_(0) {
 }
 
 
 void IncrementalMarking::TearDown() {
   delete marking_deque_memory_;
@@ skipping 404 matching lines @@
       array[new_top] = obj;
       new_top = ((new_top + 1) & mask);
       ASSERT(new_top != marking_deque_.bottom());
       ASSERT(Marking::IsGrey(Marking::MarkBitFrom(obj)));
     }
   }
   marking_deque_.set_top(new_top);
 
   steps_took_since_last_gc_ = 0;
   steps_count_since_last_gc_ = 0;
+  longest_step_ = 0.0;
 }
 
 
 void IncrementalMarking::Hurry() {
   if (state() == MARKING) {
     double start = 0.0;
     if (FLAG_trace_incremental_marking) {
       PrintF("[IncrementalMarking] Hurry\n");
       start = OS::TimeCurrentMillis();
     }
@@ skipping 136 matching lines @@
     allocation_marking_factor_ =
         static_cast<int>(allocation_marking_factor_ * 1.3);
     if (FLAG_trace_gc) {
       PrintF("Marking speed increased to %d\n", allocation_marking_factor_);
     }
   }
 
   if (FLAG_trace_incremental_marking || FLAG_trace_gc) {
     double end = OS::TimeCurrentMillis();
     double delta = (end - start);
+    longest_step_ = Max(longest_step_, delta);
     steps_took_ += delta;
     steps_took_since_last_gc_ += delta;
   }
 }
 
 
 } }  // namespace v8::internal