Oilpan: Reenable a threshold for page navigation GCs

Source/platform/heap/ThreadState.cpp

 /*
  * Copyright (C) 2013 Google Inc. 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
@@ skipping 641 matching lines @@
 {
 #if ENABLE(IDLE_GC)
     return false;
 #else
     return judgeGCThreshold(1024 * 1024, 1.5);
 #endif
 }
 
 bool ThreadState::shouldSchedulePageNavigationGC(float estimatedRemovalRatio)
 {
-    return judgeGCThreshold(1024 * 1024, 1.5);
+    return judgeGCThreshold(1024 * 1024, 1.5 * (1 - estimatedRemovalRatio));
 }
 
 bool ThreadState::shouldForceConservativeGC()
 {
     // TODO(haraken): 400% is too large. Lower the heap growing factor.
     return judgeGCThreshold(32 * 1024 * 1024, 5.0);
 }
 
 void ThreadState::schedulePageNavigationGCIfNeeded(float estimatedRemovalRatio)
 {
@@ skipping 910 matching lines @@
         json->beginArray(it->key.ascii().data());
         for (size_t age = 0; age <= maxHeapObjectAge; ++age)
             json->pushInteger(it->value.ages[age]);
         json->endArray();
     }
     TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(TRACE_DISABLED_BY_DEFAULT("blink_gc"), statsName, this, json.release());
 }
 #endif
 
 } // namespace blink