Reduce string copies in GURL creation

chrome/renderer/page_load_histograms.cc

Index: chrome/renderer/page_load_histograms.cc
diff --git a/chrome/renderer/page_load_histograms.cc b/chrome/renderer/page_load_histograms.cc
index c85428167c4bc2ab0b7145768129ac71e5180aeb..056e4227baeacb1730842a54b5dd3cf40889f850 100644
--- a/chrome/renderer/page_load_histograms.cc
+++ b/chrome/renderer/page_load_histograms.cc
@@ -23,6 +23,7 @@
 #include "chrome/renderer/searchbox/search_bouncer.h"
 #include "components/data_reduction_proxy/content/common/data_reduction_proxy_messages.h"
 #include "components/data_reduction_proxy/core/common/data_reduction_proxy_params.h"
+#include "content/public/child/url_conversion.h"
 #include "content/public/common/content_constants.h"
 #include "content/public/renderer/document_state.h"
 #include "content/public/renderer/render_frame.h"
@@ -910,14 +911,14 @@ void PageLoadHistograms::Dump(WebFrame* frame) {
     DCHECK(handled || !data_reduction_proxy_was_used);
   }
 
-  bool came_from_websearch =
-      IsFromGoogleSearchResult(frame->document().url(),
-                               GURL(frame->document().referrer()));
+  bool came_from_websearch = IsFromGoogleSearchResult(
+      frame->document().url(),
+      content::WebStringToGURL(frame->document().referrer()));
   int websearch_chrome_joint_experiment_id = kNoExperiment;
   bool is_preview = false;
   if (came_from_websearch) {
-    websearch_chrome_joint_experiment_id =
-        GetQueryStringBasedExperiment(GURL(frame->document().referrer()));
+    websearch_chrome_joint_experiment_id = GetQueryStringBasedExperiment(
+        content::WebStringToGURL(frame->document().referrer()));
     is_preview = ViaHeaderContains(frame, "1.1 Google Instant Proxy Preview");
   }