Reinstate memory pressure Oilpan GC check post V8 major GCs.

third_party/WebKit/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 652 matching lines @@
 {
     return judgeGCThreshold(512 * 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);
 }
 
+bool ThreadState::forceMemoryPressureGCIfNeeded()
+{
+    if (!shouldForceMemoryPressureGC())
+        return false;
+    completeSweep();
+    if (!shouldForceMemoryPressureGC())
+        return false;
+
+    Heap::collectGarbage(HeapPointersOnStack, GCWithoutSweep, Heap::ConservativeGC);
+    return true;
+}
+
 void ThreadState::scheduleV8FollowupGCIfNeeded(V8GCType gcType)
 {
     ASSERT(checkThread());
     Heap::reportMemoryUsageForTracing();
 
     if (isGCForbidden())
         return;
 
+    // If V8 has acted on a memory pressure signal and performed a major GC,
+    // follow up, if needed.
+    if (gcType == V8MajorGC && forceMemoryPressureGCIfNeeded())
+        return;
+
     if (isSweepingInProgress())
         return;
     ASSERT(!sweepForbidden());
 
     if (shouldScheduleV8FollowupGC())
         schedulePreciseGC();
     else if (gcType == V8MinorGC)
         scheduleIdleGC();
 }
 
@@ skipping 914 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