Add History.TopHostsVisitsByRank UMA metric.

components/history/core/browser/url_utils.cc

 // Copyright 2013 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/history/core/browser/url_utils.h"
 
 #include <algorithm>
 
+#include "base/strings/string_util.h"
 #include "url/gurl.h"
 
 namespace history {
 
 namespace {
 
 // Comparator to enforce '\0' < '?' < '#' < '/' < other characters.
 int GetURLCharPriority(char ch) {
   switch (ch) {
     case '\0': return 0;
@@ skipping 59 matching lines @@
     new_scheme = "http";
   else
     return GURL::EmptyGURL();
   url::Component comp;
   comp.len = static_cast<int>(new_scheme.length());
   GURL::Replacements replacement;
   replacement.SetScheme(new_scheme.c_str(), comp);
   return url.ReplaceComponents(replacement);
 }
 
+std::string HostForTopHosts(const GURL& url) {
+  std::string host = url.host();
+  if (StartsWithASCII(host, "www.", true))
+    host.assign(host, 4, std::string::npos);
+  return host;
+}
+
 }  // namespace history