Revert of Reduce buggy usage of the registry controlled domain service.

components/url_formatter/url_fixer.cc

 // Copyright (c) 2012 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/url_formatter/url_fixer.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 183 matching lines @@
   // Invalid file URL, just return the input.
   return text;
 }
 
 // Checks |domain| to see if a valid TLD is already present.  If not, appends
 // |desired_tld| to the domain, and prepends "www." unless it's already present.
 void AddDesiredTLD(const std::string& desired_tld, std::string* domain) {
   if (desired_tld.empty() || domain->empty())
     return;
 
-  // Abort if we already have a known TLD. In the case of an invalid host,
-  // HostHasRegistryControlledDomain will return false and we will try to
-  // append a TLD (which may make it valid). For example, "999999999999" is
-  // detected as a broken IP address and marked invalid, but attaching ".com"
-  // makes it legal.  We disallow unknown registries here so users can input
-  // "mail.yahoo" and hit ctrl-enter to get "www.mail.yahoo.com".
-  if (net::registry_controlled_domains::HostHasRegistryControlledDomain(
+  // Check the TLD.  If the return value is positive, we already have a TLD, so
+  // abort.  If the return value is std::string::npos, there's no valid host,
+  // but we can try to append a TLD anyway, since the host may become valid once
+  // the TLD is attached -- for example, "999999999999" is detected as a broken
+  // IP address and marked invalid, but attaching ".com" makes it legal.  When
+  // the return value is 0, there's a valid host with no known TLD, so we can
+  // definitely append the user's TLD.  We disallow unknown registries here so
+  // users can input "mail.yahoo" and hit ctrl-enter to get
+  // "www.mail.yahoo.com".
+  const size_t registry_length =
+      net::registry_controlled_domains::GetRegistryLength(
           *domain, net::registry_controlled_domains::EXCLUDE_UNKNOWN_REGISTRIES,
-          net::registry_controlled_domains::EXCLUDE_PRIVATE_REGISTRIES))
+          net::registry_controlled_domains::EXCLUDE_PRIVATE_REGISTRIES);
+  if ((registry_length != 0) && (registry_length != std::string::npos))
     return;
 
   // Add the suffix at the end of the domain.
   const size_t domain_length(domain->length());
   DCHECK_GT(domain_length, 0U);
   DCHECK_NE(desired_tld[0], '.');
   if ((*domain)[domain_length - 1] != '.')
     domain->push_back('.');
   domain->append(desired_tld);
 
@@ skipping 450 matching lines @@
 }
 
 bool IsEquivalentScheme(const std::string& scheme1,
                         const std::string& scheme2) {
   return scheme1 == scheme2 ||
          (scheme1 == url::kAboutScheme && scheme2 == kChromeUIScheme) ||
          (scheme1 == kChromeUIScheme && scheme2 == url::kAboutScheme);
 }
 
 }  // namespace url_formatter