Use GURLs in Physical Web data source

components/ntp_snippets/physical_web_pages/physical_web_page_suggestions_provider.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/ntp_snippets/physical_web_pages/physical_web_page_suggestions_provider.h"
 
 #include <algorithm>
 #include <memory>
 #include <string>
 #include <utility>
@@ skipping 206 matching lines @@
   // (see crbug.com/667722).
   suggestion.set_publish_date(
       base::Time::FromTimeT(static_cast<time_t>(scan_timestamp)));
   suggestion.set_publisher_name(base::UTF8ToUTF16(resolved_url.host()));
   DCHECK(base::IsStringUTF8(description));
   suggestion.set_snippet_text(base::UTF8ToUTF16(description));
   return suggestion;
 }
 
 // PhysicalWebListener implementation.
-void PhysicalWebPageSuggestionsProvider::OnFound(const std::string& url) {
+void PhysicalWebPageSuggestionsProvider::OnFound(const GURL& url) {
   FetchPhysicalWebPages();
 }
 
-void PhysicalWebPageSuggestionsProvider::OnLost(const std::string& url) {
+void PhysicalWebPageSuggestionsProvider::OnLost(const GURL& url) {
   // TODO(vitaliii): Do not refetch, but just update the current state.
   FetchPhysicalWebPages();
 }
 
 void PhysicalWebPageSuggestionsProvider::OnDistanceChanged(
-    const std::string& url,
+    const GURL& url,
     double distance_estimate) {
   FetchPhysicalWebPages();
 }
 
 }  // namespace ntp_snippets