Reduce string copies in GURL creation

content/renderer/render_frame_proxy.cc

Index: content/renderer/render_frame_proxy.cc
diff --git a/content/renderer/render_frame_proxy.cc b/content/renderer/render_frame_proxy.cc
index a44bb34e16df13f22837d12585e8f3e266bedbe7..d8effb5229f90e516b256e40ed534c172cb3438b 100644
--- a/content/renderer/render_frame_proxy.cc
+++ b/content/renderer/render_frame_proxy.cc
@@ -22,6 +22,7 @@
 #include "content/renderer/render_thread_impl.h"
 #include "content/renderer/render_view_impl.h"
 #include "content/renderer/render_widget.h"
+#include "third_party/WebKit/public/platform/URLConversion.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 #include "third_party/WebKit/public/web/WebUserGestureIndicator.h"
@@ -441,7 +442,8 @@ void RenderFrameProxy::navigate(const blink::WebURLRequest& request,
   FrameHostMsg_OpenURL_Params params;
   params.url = request.url();
   params.referrer = Referrer(
-      GURL(request.httpHeaderField(blink::WebString::fromUTF8("Referer"))),
+      blink::WebStringToGURL(
+          request.httpHeaderField(blink::WebString::fromUTF8("Referer"))),
       request.referrerPolicy());
   params.disposition = CURRENT_TAB;
   params.should_replace_current_entry = should_replace_current_entry;