Cache the mimeTypes and plugins DOM objects.

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

Index: third_party/WebKit/Source/modules/plugins/DOMPluginArray.cpp
diff --git a/third_party/WebKit/Source/modules/plugins/DOMPluginArray.cpp b/third_party/WebKit/Source/modules/plugins/DOMPluginArray.cpp
index 32d1c9683c85f25157b6b53ebee80719f089dae9..284df2193b86ac74f1f736c295037a424bee0858 100644
--- a/third_party/WebKit/Source/modules/plugins/DOMPluginArray.cpp
+++ b/third_party/WebKit/Source/modules/plugins/DOMPluginArray.cpp
@@ -29,12 +29,14 @@ namespace blink {
 
 DOMPluginArray::DOMPluginArray(LocalFrame* frame)
     : DOMWindowProperty(frame)
+    , m_modified(0)
 {
 }
 
 DEFINE_TRACE(DOMPluginArray)
 {
     DOMWindowProperty::trace(visitor);
+    visitor->trace(m_plugins);
 }
 
 unsigned DOMPluginArray::length() const
@@ -45,6 +47,20 @@ unsigned DOMPluginArray::length() const
     return data->plugins().size();
 }
 
+DOMPlugin* DOMPluginArray::getPlugin(unsigned index)
+{
+    PluginData* data = pluginData();
+    if (!data)
+        return nullptr;
+    if (data->modified() != m_modified) {
+        m_plugins.clear();
+        m_modified = data->modified();
+    }
+    if (m_plugins.find(index) == m_plugins.end())
+        m_plugins.add(index, DOMPlugin::create(data, m_frame, index));
+    return m_plugins.get(index);
+}
+
 DOMPlugin* DOMPluginArray::item(unsigned index)
 {
     PluginData* data = pluginData();
@@ -53,7 +69,7 @@ DOMPlugin* DOMPluginArray::item(unsigned index)
     const Vector<PluginInfo>& plugins = data->plugins();
     if (index >= plugins.size())
         return nullptr;
-    return DOMPlugin::create(data, m_frame, index);
+    return getPlugin(index);
 }
 
 DOMPlugin* DOMPluginArray::namedItem(const AtomicString& propertyName)
@@ -64,7 +80,7 @@ DOMPlugin* DOMPluginArray::namedItem(const AtomicString& propertyName)
     const Vector<PluginInfo>& plugins = data->plugins();
     for (unsigned i = 0; i < plugins.size(); ++i) {
         if (plugins[i].name == propertyName)
-            return DOMPlugin::create(data, m_frame, i);
+            return getPlugin(i);
     }
     return nullptr;
 }