Rewrite std::string("") to std::string(), Linux edition.

chrome/browser/extensions/api/extension_action/browser_action_apitest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "build/build_config.h"
 
 #if defined(TOOLKIT_GTK)
 #include <gtk/gtk.h>
 #endif
 
@@ skipping 674 matching lines @@
 
   WebContents* tab =
       browser()->tab_strip_model()->GetActiveWebContents();
   EXPECT_TRUE(tab != NULL);
 
   // Verify that the browser action turned the background color red.
   const std::string script =
       "window.domAutomationController.send(document.body.style."
       "backgroundColor);";
   std::string result;
-  const std::string frame_xpath = "";
-  EXPECT_TRUE(content::ExecuteScriptInFrameAndExtractString(tab,
-                                                            frame_xpath,
-                                                            script,
-                                                            &result));
+  const std::string frame_xpath;
+  EXPECT_TRUE(content::ExecuteScriptInFrameAndExtractString(
+      tab, frame_xpath, script, &result));
   EXPECT_EQ(result, "red");
 }
 
 }  // namespace
 }  // namespace extensions