Simplify the shutdown sequence of Oilpan's heap

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 217 matching lines @@
         SafePointAwareMutexLocker locker(threadAttachMutex(), BlinkGC::NoHeapPointersOnStack);
 
         // 2. Add the main thread's heap pages to the orphaned pool.
         state->cleanupPages();
 
         // 3. Detach the main thread.
         ASSERT(attachedThreads().contains(state));
         attachedThreads().remove(state);
         state->~ThreadState();
     }
-    shutdownHeapIfNecessary();
-}
-
-void ThreadState::shutdownHeapIfNecessary()
-{
-    // We don't need to enter a safe point before acquiring threadAttachMutex
-    // because this thread is already detached.
-
-    MutexLocker locker(threadAttachMutex());
-    // We start shutting down the heap if there is no running thread
-    // and Heap::shutdown() is already called.
-    if (!attachedThreads().size() && Heap::s_shutdownCalled)
-        Heap::doShutdown();
 }
 
 void ThreadState::attach()
 {
     RELEASE_ASSERT(!Heap::s_shutdownCalled);
     MutexLocker locker(threadAttachMutex());
     ThreadState* state = new ThreadState();
     attachedThreads().add(state);
 }
 
@@ skipping 55 matching lines @@
         attachedThreads().remove(this);
     }
 }
 
 void ThreadState::detach()
 {
     ThreadState* state = current();
     state->cleanup();
     RELEASE_ASSERT(state->gcState() == ThreadState::NoGCScheduled);
     delete state;
-    shutdownHeapIfNecessary();
 }
 
 void ThreadState::visitPersistentRoots(Visitor* visitor)
 {
     TRACE_EVENT0("blink_gc", "ThreadState::visitPersistentRoots");
     Heap::crossThreadPersistentRegion().tracePersistentNodes(visitor);
 
     for (ThreadState* state : attachedThreads())
         state->visitPersistents(visitor);
 }
@@ skipping 1207 matching lines @@
     threadDump->addScalar("dead_count", "objects", totalDeadCount);
     threadDump->addScalar("live_size", "bytes", totalLiveSize);
     threadDump->addScalar("dead_size", "bytes", totalDeadSize);
 
     WebMemoryAllocatorDump* heapsDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(heapsDumpName);
     WebMemoryAllocatorDump* classesDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(classesDumpName);
     BlinkGCMemoryDumpProvider::instance()->currentProcessMemoryDump()->addOwnershipEdge(classesDump->guid(), heapsDump->guid());
 }
 
 } // namespace blink