Oilpan: clear out AsyncCallChainMaps in an orderly manner.

Source/core/inspector/AsyncCallStackTracker.h

 /*
  * 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 52 matching lines @@
         AsyncCallStack(const String&, const ScriptValue&);
         ~AsyncCallStack();
         void trace(Visitor*) { }
         String description() const { return m_description; }
         ScriptValue callFrames() const { return m_callFrames; }
     private:
         String m_description;
         ScriptValue m_callFrames;
     };
 
-    typedef WillBeHeapDeque<RefPtrWillBeMember<AsyncCallStack>, 4> AsyncCallStackVector;
+    using AsyncCallStackVector = WillBeHeapDeque<RefPtrWillBeMember<AsyncCallStack>, 4>;
 
     class AsyncCallChain final : public RefCountedWillBeGarbageCollectedFinalized<AsyncCallChain> {
     public:
         AsyncCallChain() { }
         explicit AsyncCallChain(const AsyncCallChain& t) : m_callStacks(t.m_callStacks) { }
         AsyncCallStackVector callStacks() const { return m_callStacks; }
         void trace(Visitor*);
     private:
         friend class AsyncCallStackTracker;
         AsyncCallStackVector m_callStacks;
@@ skipping 68 matching lines @@
     void setCurrentAsyncCallChain(ExecutionContext*, PassRefPtrWillBeRawPtr<AsyncCallChain>);
     void clearCurrentAsyncCallChain();
     static void ensureMaxAsyncCallChainDepth(AsyncCallChain*, unsigned);
     bool validateCallFrames(const ScriptValue& callFrames);
 
     ExecutionContextData* createContextDataIfNeeded(ExecutionContext*);
 
     unsigned m_maxAsyncCallStackDepth;
     RefPtrWillBeMember<AsyncCallChain> m_currentAsyncCallChain;
     unsigned m_nestedAsyncCallCount;
-    typedef WillBeHeapHashMap<RawPtrWillBeMember<ExecutionContext>, OwnPtrWillBeMember<ExecutionContextData> > ExecutionContextDataMap;
+
+    using ExecutionContextDataMap = WillBeHeapHashMap<RawPtrWillBeMember<ExecutionContext>, OwnPtrWillBeMember<ExecutionContextData>>;
     ExecutionContextDataMap m_executionContextDataMap;
+
     Listener* m_listener;
     ScriptDebugServer* m_scriptDebugServer;
 };
 
 } // namespace blink
 
 #endif // !defined(AsyncCallStackTracker_h)