Remove unused reference to DownloadManager in PluginInstaller

chrome/browser/plugins/plugin_installer.h

Index: chrome/browser/plugins/plugin_installer.h
diff --git a/chrome/browser/plugins/plugin_installer.h b/chrome/browser/plugins/plugin_installer.h
index 36b7eb3cb8b640e72e8a5816a63da55a96d65c83..9504be174d8e10d4f0cadf2fd71db0c191522fd1 100644
--- a/chrome/browser/plugins/plugin_installer.h
+++ b/chrome/browser/plugins/plugin_installer.h
@@ -55,9 +55,7 @@ class PluginInstaller : public content::DownloadItem::Observer {
                        content::WebContents* web_contents);
 
  private:
-  void DownloadStarted(scoped_refptr<content::DownloadManager> dlm,
-                       content::DownloadItem* item,
-                       net::Error error);
+  void DownloadStarted(content::DownloadItem* item, net::Error error);
   void DownloadError(const std::string& msg);
   void DownloadCancelled();