[WIP] make GURL::path() return a StringPiece

chrome/browser/search/most_visited_iframe_source.cc

Index: chrome/browser/search/most_visited_iframe_source.cc
diff --git a/chrome/browser/search/most_visited_iframe_source.cc b/chrome/browser/search/most_visited_iframe_source.cc
index 7dbb0497273480b4c47cce414e0662a6a76f3576..6eb5e8981581ad70c7e0c37189a52dbd7b221656 100644
--- a/chrome/browser/search/most_visited_iframe_source.cc
+++ b/chrome/browser/search/most_visited_iframe_source.cc
@@ -49,12 +49,12 @@ void MostVisitedIframeSource::StartDataRequest(
     const content::ResourceRequestInfo::WebContentsGetter& wc_getter,
     const content::URLDataSource::GotDataCallback& callback) {
   GURL url(chrome::kChromeSearchMostVisitedUrl + path_and_query);
-  std::string path(url.path());
+  base::StringPiece path(url.path());
 
 #if !defined(GOOGLE_CHROME_BUILD)
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   if (command_line->HasSwitch(switches::kLocalNtpReload)) {
-    std::string rel_path = "most_visited_" + path.substr(1);
+    std::string rel_path = "most_visited_" + path.substr(1).as_string();
     if (path == kSingleJSPath) {
       std::string origin;
       if (!GetOrigin(wc_getter, &origin)) {