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

url/gurl.h

Index: url/gurl.h
diff --git a/url/gurl.h b/url/gurl.h
index 5753230db769ad079ac1041a8d5025d441898f58..0cea864f779ac47c4e2e8bfbf985c49b2ab78a9c 100644
--- a/url/gurl.h
+++ b/url/gurl.h
@@ -323,9 +323,8 @@ class URL_EXPORT GURL {
   bool has_path() const {
     return parsed_.path.len >= 0;
   }
-  std::string path() const {
-    return ComponentString(parsed_.path);
-  }
+
+  base::StringPiece path() const { return ComponentStringPiece(parsed_.path); }
   base::StringPiece path_piece() const {
     return ComponentStringPiece(parsed_.path);
   }