diff --git a/mozilla/dom/src/base/nsGlobalWindow.cpp b/mozilla/dom/src/base/nsGlobalWindow.cpp
index d0604a125cf..5fb623c5065 100644
--- a/mozilla/dom/src/base/nsGlobalWindow.cpp
+++ b/mozilla/dom/src/base/nsGlobalWindow.cpp
@@ -4327,6 +4327,15 @@ NavigatorImpl::Preference()
 }
 
 
+nsresult
+NavigatorImpl::RefreshMIMEArray()
+{
+  nsresult rv = NS_OK;
+  if (mMimeTypes)
+    rv = mMimeTypes->Refresh();
+  return rv;
+}
+
 #ifdef XP_MAC
 #pragma mark -
 #endif
diff --git a/mozilla/dom/src/base/nsGlobalWindow.h b/mozilla/dom/src/base/nsGlobalWindow.h
index bea6900a08f..6752042f01b 100644
--- a/mozilla/dom/src/base/nsGlobalWindow.h
+++ b/mozilla/dom/src/base/nsGlobalWindow.h
@@ -59,6 +59,7 @@
 #include "nsISidebar.h"
 #include "nsIPrincipal.h"
 #include "nsPluginArray.h"
+#include "nsMimeTypeArray.h"
 #include "nsIXPCScriptable.h"
 
 #define DEFAULT_HOME_PAGE "www.mozilla.org"
@@ -293,11 +294,12 @@ public:
   NS_DECL_ISUPPORTS
   NS_DECL_NSIDOMNAVIGATOR
   NS_DECL_NSIDOMJSNAVIGATOR
-
+  
   void SetDocShell(nsIDocShell *aDocShell);
+  nsresult RefreshMIMEArray();
 
 protected:
-  nsIDOMMimeTypeArray* mMimeTypes;
+  MimeTypeArrayImpl* mMimeTypes;
   PluginArrayImpl* mPlugins;
   nsIDocShell* mDocShell; // weak reference
 };
diff --git a/mozilla/dom/src/base/nsMimeTypeArray.cpp b/mozilla/dom/src/base/nsMimeTypeArray.cpp
index 52d53df45d8..eb3b19db30e 100644
--- a/mozilla/dom/src/base/nsMimeTypeArray.cpp
+++ b/mozilla/dom/src/base/nsMimeTypeArray.cpp
@@ -40,12 +40,7 @@ MimeTypeArrayImpl::MimeTypeArrayImpl(nsIDOMNavigator* navigator)
 
 MimeTypeArrayImpl::~MimeTypeArrayImpl()
 {
-	if (mMimeTypeArray != nsnull) {
-		for (PRUint32 i = 0; i < mMimeTypeCount; i++) {
-			NS_IF_RELEASE(mMimeTypeArray[i]);
-		}
-		delete[] mMimeTypeArray;
-	}
+  Clear();
 }
 
 
@@ -122,8 +117,29 @@ MimeTypeArrayImpl::NamedItem(const nsAReadableString& aName,
   return NS_OK;
 }
 
+void  MimeTypeArrayImpl::Clear()
+{
+  if (mMimeTypeArray != nsnull) {
+    for (PRUint32 i = 0; i < mMimeTypeCount; i++) {
+      NS_IF_RELEASE(mMimeTypeArray[i]);
+    }
+    delete[] mMimeTypeArray;
+    mMimeTypeArray = nsnull;
+  }
+  mMimeTypeCount = 0;
+}
+
+nsresult MimeTypeArrayImpl::Refresh()
+{
+  Clear();
+  return GetMimeTypes();
+}
+
 nsresult MimeTypeArrayImpl::GetMimeTypes()
 {
+  NS_PRECONDITION(!mMimeTypeArray && mMimeTypeCount==0,
+                      "already initialized");
+
 	nsIDOMPluginArray* pluginArray = nsnull;
 	nsresult rv = mNavigator->GetPlugins(&pluginArray);
 	if (rv == NS_OK) {
diff --git a/mozilla/dom/src/base/nsMimeTypeArray.h b/mozilla/dom/src/base/nsMimeTypeArray.h
index ac6b38a2cd6..64a2546d7cd 100644
--- a/mozilla/dom/src/base/nsMimeTypeArray.h
+++ b/mozilla/dom/src/base/nsMimeTypeArray.h
@@ -39,9 +39,11 @@ public:
 	NS_IMETHOD GetLength(PRUint32* aLength);
 	NS_IMETHOD Item(PRUint32 aIndex, nsIDOMMimeType** aReturn);
 	NS_IMETHOD NamedItem(const nsAReadableString& aName, nsIDOMMimeType** aReturn);
+	nsresult   Refresh();
 
 private:
-	nsresult GetMimeTypes();
+  nsresult GetMimeTypes();
+  void     Clear();
 
 protected:
 	nsIDOMNavigator* mNavigator;
diff --git a/mozilla/dom/src/base/nsPluginArray.cpp b/mozilla/dom/src/base/nsPluginArray.cpp
index b26d25ae53e..9774403a3cc 100644
--- a/mozilla/dom/src/base/nsPluginArray.cpp
+++ b/mozilla/dom/src/base/nsPluginArray.cpp
@@ -23,6 +23,7 @@
 
 #include "nsPluginArray.h"
 #include "nsMimeTypeArray.h"
+#include "nsGlobalWindow.h"
 #include "nsIScriptGlobalObject.h"
 #include "nsIDOMNavigator.h"
 #include "nsIDOMMimeType.h"
@@ -34,7 +35,7 @@
 
 static NS_DEFINE_CID(kPluginManagerCID, NS_PLUGINMANAGER_CID);
 
-PluginArrayImpl::PluginArrayImpl(nsIDOMNavigator* navigator,
+PluginArrayImpl::PluginArrayImpl(NavigatorImpl* navigator,
                                  nsIDocShell *aDocShell)
 {
   nsresult rv;
@@ -183,6 +184,9 @@ PluginArrayImpl::Refresh(PRBool aReloadDocuments)
   if(pm)
     pm->ReloadPlugins(aReloadDocuments);
 
+  if (mNavigator)
+    mNavigator->RefreshMIMEArray();
+  
   if (aReloadDocuments && mDocShell) {
     nsCOMPtr<nsIWebNavigation> webNav(do_QueryInterface(mDocShell));
 
diff --git a/mozilla/dom/src/base/nsPluginArray.h b/mozilla/dom/src/base/nsPluginArray.h
index b5ed32ff158..4c45aaf26d8 100644
--- a/mozilla/dom/src/base/nsPluginArray.h
+++ b/mozilla/dom/src/base/nsPluginArray.h
@@ -27,7 +27,7 @@
 #include "nsIDOMPlugin.h"
 #include "nsIPluginHost.h"
 
-class nsIDOMNavigator;
+class NavigatorImpl;
 class nsIDocShell;
 struct nsIPluginHost;
 
@@ -35,7 +35,7 @@ class PluginArrayImpl : public nsIDOMPluginArray,
                         public nsIDOMJSPluginArray
 {
 public:
-  PluginArrayImpl(nsIDOMNavigator* navigator, nsIDocShell *aDocShell);
+  PluginArrayImpl(NavigatorImpl* navigator, nsIDocShell *aDocShell);
   virtual ~PluginArrayImpl();
 
   NS_DECL_ISUPPORTS
@@ -55,7 +55,7 @@ public:
   void SetDocShell(nsIDocShell* aDocShell);
 
 protected:
-  nsIDOMNavigator* mNavigator;
+  NavigatorImpl* mNavigator;
   nsCOMPtr<nsIPluginHost> mPluginHost;
   PRUint32 mPluginCount;
   nsIDOMPlugin** mPluginArray;