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

chrome/browser/supervised_user/supervised_user_url_filter.cc

Index: chrome/browser/supervised_user/supervised_user_url_filter.cc
diff --git a/chrome/browser/supervised_user/supervised_user_url_filter.cc b/chrome/browser/supervised_user/supervised_user_url_filter.cc
index 0fd9c7db713c657689335ca0433e3e3e436f7067..808a5b8a0985e9242f099a9d39e573acc29ab005 100644
--- a/chrome/browser/supervised_user/supervised_user_url_filter.cc
+++ b/chrome/browser/supervised_user/supervised_user_url_filter.cc
@@ -565,7 +565,8 @@ GURL SupervisedUserURLFilter::GetEmbeddedURL(const GURL& url) const {
   if (url.DomainIs(kAmpCacheHost)) {
     std::string s;
     std::string embedded;
-    if (re2::RE2::FullMatch(url.path(), amp_cache_path_regex_, &s, &embedded)) {
+    if (re2::RE2::FullMatch(url.path().as_string(), amp_cache_path_regex_, &s,
+                            &embedded)) {
       if (url.has_query())
         embedded += "?" + url.query();
       return BuildURL(!s.empty(), embedded);
@@ -578,8 +579,8 @@ GURL SupervisedUserURLFilter::GetEmbeddedURL(const GURL& url) const {
           google_util::DISALLOW_NON_STANDARD_PORTS)) {
     std::string s;
     std::string embedded;
-    if (re2::RE2::FullMatch(url.path(), google_amp_viewer_path_regex_, &s,
-                            &embedded)) {
+    if (re2::RE2::FullMatch(url.path().as_string(),
+                            google_amp_viewer_path_regex_, &s, &embedded)) {
       // The embedded URL may be percent-encoded. Undo that.
       embedded = net::UnescapeURLComponent(
           embedded,