Cache the mimeTypes and plugins DOM objects.

third_party/WebKit/Source/modules/plugins/DOMPluginArray.h

 /*
     Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
     Copyright (C) 2008 Apple Inc. All rights reserved.
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.
 
     This library is distributed in the hope that it will be useful,
@@ skipping 24 matching lines @@
 class DOMPluginArray final : public GarbageCollected<DOMPluginArray>, public ScriptWrappable, public DOMWindowProperty {
     DEFINE_WRAPPERTYPEINFO();
     USING_GARBAGE_COLLECTED_MIXIN(DOMPluginArray);
 public:
     static DOMPluginArray* create(LocalFrame* frame)
     {
         return new DOMPluginArray(frame);
     }
 
     unsigned length() const;
+    DOMPlugin* getPlugin(unsigned index);
     DOMPlugin* item(unsigned index);
     DOMPlugin* namedItem(const AtomicString& propertyName);
 
     void refresh(bool reload);
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     explicit DOMPluginArray(LocalFrame*);
     PluginData* pluginData() const;
+    using PluginMap = HeapHashMap<unsigned, Member<DOMPlugin>, DefaultHash<unsigned>::Hash, WTF::UnsignedWithZeroKeyHashTraits<unsigned>>;
+    PluginMap m_plugins;
+    double m_modified;
 };
 
 } // namespace blink
 
 #endif // DOMPluginArray_h