Use size_t in GCIdleTimeHandler to fix undefined behaviour.

src/heap/spaces.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/base/platform/platform.h"
 #include "src/full-codegen.h"
 #include "src/heap/mark-compact.h"
 #include "src/macro-assembler.h"
@@ skipping 2717 matching lines @@
 void PagedSpace::ReportStatistics() {
   int pct = static_cast<int>(Available() * 100 / Capacity());
   PrintF("  capacity: %" V8_PTR_PREFIX
          "d"
          ", waste: %" V8_PTR_PREFIX
          "d"
          ", available: %" V8_PTR_PREFIX "d, %%%d\n",
          Capacity(), Waste(), Available(), pct);
 
   if (!swept_precisely_) return;
+  if (heap()->mark_compact_collector()->sweeping_in_progress()) {
+    heap()->mark_compact_collector()->EnsureSweepingCompleted();
+  }
   ClearHistograms(heap()->isolate());
   HeapObjectIterator obj_it(this);
   for (HeapObject* obj = obj_it.Next(); obj != NULL; obj = obj_it.Next())
     CollectHistogramInfo(obj);
   ReportHistogram(heap()->isolate(), true);
 }
 #endif
 
 
 // -----------------------------------------------------------------------------
@@ skipping 351 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }
 }  // namespace v8::internal