Reduce context disposal gc overhead.

src/heap/gc-tracer.h

 // Copyright 2014 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.
 
 #ifndef V8_HEAP_GC_TRACER_H_
 #define V8_HEAP_GC_TRACER_H_
 
 #include "src/base/platform/platform.h"
 
 namespace v8 {
@@ skipping 230 matching lines @@
     double pure_incremental_marking_duration;
 
     // Longest incremental marking step since start of marking.
     // (value at start of event)
     double longest_incremental_marking_step;
 
     // Amounts of time spent in different scopes during GC.
     double scopes[Scope::NUMBER_OF_SCOPES];
   };
 
-  static const int kRingBufferMaxSize = 10;
+  static const size_t kRingBufferMaxSize = 10;
 
   typedef RingBuffer<Event, kRingBufferMaxSize> EventBuffer;
 
   typedef RingBuffer<AllocationEvent, kRingBufferMaxSize> AllocationEventBuffer;
 
   typedef RingBuffer<ContextDisposalEvent, kRingBufferMaxSize>
       ContextDisposalEventBuffer;
 
   explicit GCTracer(Heap* heap);
 
@@ skipping 156 matching lines @@
   // Holds the new space top pointer recorded at the end of the last garbage
   // collection.
   intptr_t new_space_top_after_gc_;
 
   DISALLOW_COPY_AND_ASSIGN(GCTracer);
 };
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_GC_TRACER_H_