Add backup URL support for SafeBrowsing data requests.

chrome/browser/safe_browsing/safe_browsing_service.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 "chrome/browser/safe_browsing/safe_browsing_service.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/command_line.h"
@@ skipping 40 matching lines @@
 namespace {
 
 // Filename suffix for the cookie database.
 const FilePath::CharType kCookiesFile[] = FILE_PATH_LITERAL(" Cookies");
 
 // The default URL prefix where browser fetches chunk updates, hashes,
 // and reports safe browsing hits and malware details.
 const char* const kSbDefaultURLPrefix =
     "https://safebrowsing.google.com/safebrowsing";
 
+// The backup URL prefix used when there are issues establishing a connection
+// with the server at the primary URL.
+const char* const kSbBackupConnectErrorURLPrefix =
+    "https://alt1-safebrowsing.google.com/safebrowsing";
+
+// The backup URL prefix used when there are HTTP-specific issues with the
+// server at the primary URL.
+const char* const kSbBackupHttpErrorURLPrefix =
+    "https://alt2-safebrowsing.google.com/safebrowsing";
+
+// The backup URL prefix used when there are local network specific issues.
+const char* const kSbBackupNetworkErrorURLPrefix =
+    "https://alt3-safebrowsing.google.com/safebrowsing";

[noelutz, 2013/01/15 01:46:49]

Just curious. In the CL description you mention that you want to handle DNS
resolution issues.  I was expecting one of these backup URLs to have an IP for
hostname to avoid DNS resolution altogether.  Am I misunderstanding something?

[noelutz, 2013/01/15 18:04:07]

Still curious about that ;).

[cbentzel, 2013/01/22 20:04:30]

Sorry - it may be reasonable to do a raw IP only. One concern is possible load
on a single IP (not necessarily single IP), especially since we probably we may
not be able to use anycast here.

+
 FilePath CookieFilePath() {
   return FilePath(
       SafeBrowsingService::GetBaseFilename().value() + kCookiesFile);
 }
 
 }  // namespace
 
 class SafeBrowsingURLRequestContextGetter
     : public net::URLRequestContextGetter {
  public:
@@ skipping 263 matching lines @@
 #endif
 #endif
   CommandLine* cmdline = CommandLine::ForCurrentProcess();
   config.disable_auto_update =
       cmdline->HasSwitch(switches::kSbDisableAutoUpdate) ||
       cmdline->HasSwitch(switches::kDisableBackgroundNetworking);
   config.url_prefix =
       cmdline->HasSwitch(switches::kSbURLPrefix) ?
       cmdline->GetSwitchValueASCII(switches::kSbURLPrefix) :
       kSbDefaultURLPrefix;
+  config.backup_connect_error_url_prefix = kSbBackupConnectErrorURLPrefix;
+  config.backup_http_error_url_prefix = kSbBackupHttpErrorURLPrefix;
+  config.backup_network_error_url_prefix = kSbBackupNetworkErrorURLPrefix;
 
 #if defined(FULL_SAFE_BROWSING)
   DCHECK(database_manager_);
   database_manager_->StartOnIOThread();
 
   DCHECK(!protocol_manager_);
   protocol_manager_ =
       SafeBrowsingProtocolManager::Create(database_manager_,
                                           url_request_context_getter_,
                                           config);
@@ skipping 106 matching lines @@
 #if defined(FULL_SAFE_BROWSING)
   if (csd_service_.get())
     csd_service_->SetEnabledAndRefreshState(enable);
   if (download_service_.get()) {
     download_service_->SetEnabled(
         enable && !CommandLine::ForCurrentProcess()->HasSwitch(
             switches::kDisableImprovedDownloadProtection));
   }
 #endif
 }