Another 64->32 bit warning from the Windows compiler.

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 844 matching lines @@
     speed_up = true;
   }
 
   if (speed_up) {
     if (state_ != MARKING) {
       if (FLAG_trace_gc) {
         PrintF("Postponing speeding up marking until marking starts\n");
       }
     } else {
       allocation_marking_factor_ += kAllocationMarkingFactorSpeedup;
-      allocation_marking_factor_ =
+      allocation_marking_factor_ = static_cast<int>(
           Min(kMaxAllocationMarkingFactor,
-              static_cast<intptr_t>(allocation_marking_factor_ * 1.3));
+              static_cast<intptr_t>(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);
@@ skipping 17 matching lines @@
   allocation_marking_factor_ = kInitialAllocationMarkingFactor;
   bytes_scanned_ = 0;
 }
 
 
 int64_t IncrementalMarking::SpaceLeftInOldSpace() {
   return heap_->MaxOldGenerationSize() - heap_->PromotedSpaceSize();
 }
 
 } }  // namespace v8::internal