Cache the mimeTypes and plugins DOM objects.

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

Index: third_party/WebKit/Source/modules/plugins/DOMMimeTypeArray.cpp
diff --git a/third_party/WebKit/Source/modules/plugins/DOMMimeTypeArray.cpp b/third_party/WebKit/Source/modules/plugins/DOMMimeTypeArray.cpp
index 95b464dd1f1bb865ac19059edadf29da666724f2..2e4eab3565bb9a664d3f084e2e14c7d1162f14f1 100644
--- a/third_party/WebKit/Source/modules/plugins/DOMMimeTypeArray.cpp
+++ b/third_party/WebKit/Source/modules/plugins/DOMMimeTypeArray.cpp
@@ -29,12 +29,14 @@ namespace blink {
 
 DOMMimeTypeArray::DOMMimeTypeArray(LocalFrame* frame)
     : DOMWindowProperty(frame)
+    , m_modified(0)
 {
 }
 
 DEFINE_TRACE(DOMMimeTypeArray)
 {
     DOMWindowProperty::trace(visitor);
+    visitor->trace(m_mimeTypes);
 }
 
 unsigned DOMMimeTypeArray::length() const
@@ -45,6 +47,20 @@ unsigned DOMMimeTypeArray::length() const
     return data->mimes().size();
 }
 
+DOMMimeType* DOMMimeTypeArray::getMimeType(unsigned index)
+{
+    PluginData* data = getPluginData();
+    if (!data)
+        return nullptr;
+    if (data->modified() != m_modified) {
+        m_mimeTypes.clear();
+        m_modified = data->modified();
+    }
+    if (m_mimeTypes.find(index) == m_mimeTypes.end())
+        m_mimeTypes.add(index, DOMMimeType::create(data, m_frame, index));
+    return m_mimeTypes.get(index);
+}
+
 DOMMimeType* DOMMimeTypeArray::item(unsigned index)
 {
     PluginData* data = getPluginData();
@@ -53,7 +69,7 @@ DOMMimeType* DOMMimeTypeArray::item(unsigned index)
     const Vector<MimeClassInfo>& mimes = data->mimes();
     if (index >= mimes.size())
         return nullptr;
-    return DOMMimeType::create(data, m_frame, index);
+    return getMimeType(index);
 }
 
 DOMMimeType* DOMMimeTypeArray::namedItem(const AtomicString& propertyName)
@@ -64,7 +80,7 @@ DOMMimeType* DOMMimeTypeArray::namedItem(const AtomicString& propertyName)
     const Vector<MimeClassInfo>& mimes = data->mimes();
     for (unsigned i = 0; i < mimes.size(); ++i) {
         if (mimes[i].type == propertyName)
-            return DOMMimeType::create(data, m_frame, i);
+            return getMimeType(i);
     }
     return nullptr;
 }