Make scan-on-scavenge less verbose.

src/heap.h

 // 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 876 matching lines @@
 
   // Notify the heap that a context has been disposed.
   int NotifyContextDisposed() { return ++contexts_disposed_; }
 
   // Utility to invoke the scavenger. This is needed in test code to
   // ensure correct callback for weak global handles.
   void PerformScavenge();
 
   inline void increment_scan_on_scavenge_pages() {
     scan_on_scavenge_pages_++;
-    if (FLAG_trace_gc) {
+    if (FLAG_trace_gc_verbose) {
       PrintF("Scan-on-scavenge pages: %d\n", scan_on_scavenge_pages_);
     }
   }
 
   inline void decrement_scan_on_scavenge_pages() {
     scan_on_scavenge_pages_--;
-    if (FLAG_trace_gc) {
+    if (FLAG_trace_gc_verbose) {
       PrintF("Scan-on-scavenge pages: %d\n", scan_on_scavenge_pages_);
     }
   }
 
   PromotionQueue* promotion_queue() { return &promotion_queue_; }
 
 #ifdef DEBUG
   // Utility used with flag gc-greedy.
   void GarbageCollectionGreedyCheck();
 #endif
@@ skipping 1423 matching lines @@
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 } }  // namespace v8::internal
 
 #undef HEAP
 
 #endif  // V8_HEAP_H_