Add base:: to string16s in chrome/.

chrome/test/base/in_process_browser_test_browsertest.cc

Index: chrome/test/base/in_process_browser_test_browsertest.cc
diff --git a/chrome/test/base/in_process_browser_test_browsertest.cc b/chrome/test/base/in_process_browser_test_browsertest.cc
index 5272c35bfff5d7711cfaf8365bfe4b6a0fa28e46..7ab6d5e49cefea921cdefdc760fa5218b03b049a 100644
--- a/chrome/test/base/in_process_browser_test_browsertest.cc
+++ b/chrome/test/base/in_process_browser_test_browsertest.cc
@@ -39,11 +39,11 @@ class LoadFailObserver : public content::WebContentsObserver {
 
   virtual void DidFailProvisionalLoad(
       int64 frame_id,
-      const string16& frame_unique_name,
+      const base::string16& frame_unique_name,
       bool is_main_frame,
       const GURL& validated_url,
       int error_code,
-      const string16& error_description,
+      const base::string16& error_description,
       content::RenderViewHost* render_view_host) OVERRIDE {
     failed_load_ = true;
     error_code_ = static_cast<net::Error>(error_code);