Add backup URL support for SafeBrowsing data requests.

chrome/browser/safe_browsing/safe_browsing_service.cc

Index: chrome/browser/safe_browsing/safe_browsing_service.cc
diff --git a/chrome/browser/safe_browsing/safe_browsing_service.cc b/chrome/browser/safe_browsing/safe_browsing_service.cc
index b957300e6a2278adcc248be6119ebcfb90716bcc..65e1f1b73ee81761fd7dcca611831b84b80f98f1 100644
--- a/chrome/browser/safe_browsing/safe_browsing_service.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_service.cc
@@ -58,6 +58,20 @@ const FilePath::CharType kCookiesFile[] = FILE_PATH_LITERAL(" Cookies");
 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);
@@ -341,6 +355,9 @@ void SafeBrowsingService::StartOnIOThread() {
       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_);