Convert string16 to base::string16 in content.

content/browser/site_per_process_browsertest.cc

Index: content/browser/site_per_process_browsertest.cc
diff --git a/content/browser/site_per_process_browsertest.cc b/content/browser/site_per_process_browsertest.cc
index f32e1e93822626f7f5fa561a4504b7c453844acc..cca1df07c00f07aec94356c46682eb2f9e412746 100644
--- a/content/browser/site_per_process_browsertest.cc
+++ b/content/browser/site_per_process_browsertest.cc
@@ -36,11 +36,11 @@ class SitePerProcessWebContentsObserver: public 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,
       RenderViewHost* render_view_host) OVERRIDE {
     navigation_url_ = validated_url;
     navigation_succeeded_ = false;
@@ -48,7 +48,7 @@ class SitePerProcessWebContentsObserver: public WebContentsObserver {
 
   virtual void DidCommitProvisionalLoadForFrame(
       int64 frame_id,
-      const string16& frame_unique_name,
+      const base::string16& frame_unique_name,
       bool is_main_frame,
       const GURL& url,
       PageTransition transition_type,