Refactor: Make PyAuto InstallExtension() take a string. Delete dead code.

chrome/test/pyautolib/pyautolib.cc

Index: chrome/test/pyautolib/pyautolib.cc
diff --git a/chrome/test/pyautolib/pyautolib.cc b/chrome/test/pyautolib/pyautolib.cc
index 3db59eb2682ff41d710a798d67b91eb94770dbc7..62714cf2334fcf0f44f04141c94f5610343589aa 100644
--- a/chrome/test/pyautolib/pyautolib.cc
+++ b/chrome/test/pyautolib/pyautolib.cc
@@ -202,10 +202,10 @@ int PyUITestBase::GetBrowserWindowCount() {
   return num_windows;
 }
 
-std::string PyUITestBase::InstallExtension(const FilePath& crx_file,
+std::string PyUITestBase::InstallExtension(const std::string& extension_path,
                                            bool with_ui) {
   scoped_refptr<ExtensionProxy> proxy =
-      automation()->InstallExtension(crx_file, with_ui);
+      automation()->InstallExtension(extension_path, with_ui);
   std::string id;
   if (!proxy.get() || !proxy.get()->GetId(&id))
     return "";