AU: Retry up to 3 times 30 seconds apart on HTTP response code 0.

update_attempter.cc

Index: update_attempter.cc
diff --git a/update_attempter.cc b/update_attempter.cc
index 4e7d7bf586b64be10db6aa22237b66b75e8ab315..7c958cb777fb07fd7a8ec17bd0e2e8eb849fda23 100644
--- a/update_attempter.cc
+++ b/update_attempter.cc
@@ -162,11 +162,18 @@ void UpdateAttempter::Update(const std::string& app_version,
   processor_->set_delegate(this);
 
   // Actions:
+  LibcurlHttpFetcher* update_check_fetcher =
+      new LibcurlHttpFetcher(GetProxyResolver());
+  // If this is an automatic check, try harder to connect to the network. See
+  // comment in libcurl_http_fetcher.cc.
+  if (!obey_proxies) {
+    update_check_fetcher->set_no_network_max_retries(3);
+  }
   shared_ptr<OmahaRequestAction> update_check_action(
       new OmahaRequestAction(prefs_,
                              omaha_request_params_,
                              NULL,
-                             new LibcurlHttpFetcher(GetProxyResolver())));
+                             update_check_fetcher));  // passes ownership
   shared_ptr<OmahaResponseHandlerAction> response_handler_action(
       new OmahaResponseHandlerAction(prefs_));
   shared_ptr<FilesystemCopierAction> filesystem_copier_action(