From: Ubuntu
Subject: introduce a pref to prefer certain plugins for mime-types

diff --git a/dom/plugins/base/nsPluginHost.cpp b/dom/plugins/base/nsPluginHost.cpp
--- a/dom/plugins/base/nsPluginHost.cpp
+++ b/dom/plugins/base/nsPluginHost.cpp
@@ -1561,17 +1561,45 @@ nsPluginHost::FindPluginForType(const ch
                                 bool aCheckEnabled)
 {
   if (!aMimeType) {
     return nsnull;
   }
 
   LoadPlugins();
 
+  char *preferredPluginPath = NULL;
+  nsCAutoString mimetypePrefString ("modules.plugins.mimetype.");
+  mimetypePrefString.Append(aMimeType);
+  const char *mimetypePrefChar = mimetypePrefString.get();
+  nsAdoptingCString pluginPath = Preferences::GetCString(mimetypePrefChar);
+  preferredPluginPath = (char*) pluginPath.get();
+
   nsPluginTag *plugin = mPlugins;
+
+  if(preferredPluginPath) {
+    while (nsnull != plugin) {
+      if (0 == PL_strcasecmp(plugin->mFileName.get(), preferredPluginPath) ||
+          0 == PL_strcasecmp(plugin->mFullPath.get(), preferredPluginPath)) {
+        return plugin;
+      }
+      plugin = plugin->mNext;
+    }
+
+    // now lets search for substrings
+    plugin = mPlugins;
+    while (nsnull != plugin) {
+      if (nsnull != PL_strstr(plugin->mFileName.get(), preferredPluginPath) ||
+          nsnull != PL_strstr(plugin->mFullPath.get(), preferredPluginPath)) {
+        return plugin;
+      }
+      plugin = plugin->mNext;
+    }
+  }
+
   while (plugin) {
     if (!aCheckEnabled || plugin->IsEnabled()) {
       PRInt32 mimeCount = plugin->mMimeTypes.Length();
       for (PRInt32 i = 0; i < mimeCount; i++) {
         if (0 == PL_strcasecmp(plugin->mMimeTypes[i].get(), aMimeType)) {
           return plugin;
         }
       }