Display DNS probe results.

chrome/common/net/net_error_info.h

 // Copyright (c) 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.
 
 #ifndef CHROME_COMMON_NET_NET_ERROR_INFO_H_
 #define CHROME_COMMON_NET_NET_ERROR_INFO_H_
 
 namespace chrome_common_net {
 
-enum DnsProbeResult {
-  DNS_PROBE_UNKNOWN,
-  DNS_PROBE_NO_INTERNET,
-  DNS_PROBE_BAD_CONFIG,
-  DNS_PROBE_NXDOMAIN,
+// The status of a DNS probe that the NetErrorTabHelper may or may not have
+// started.
+enum DnsProbeStatus {
+  // A DNS probe may be run for this error page.  (This status is only used on
+  // the renderer side before it's received a status update from the browser.)
+  DNS_PROBE_POSSIBLE,
+
+  // A DNS probe will not be run for this error page.  (This happens if the
+  // user has the "Use web service to resolve navigation errors" preference
+  // turned off, or if probes are disabled by the field trial.)
+  DNS_PROBE_NOT_RUN,
+
+  // A DNS probe has been started for this error page.  The renderer should
+  // expect to receive another IPC with one of the FINISHED statuses once the
+  // probe has finished (as long as the error page is still loaded).
+  DNS_PROBE_STARTED,
+
+  // A DNS probe has finished with one of the following results:
+
+  // The probe was inconclusive..
+  DNS_PROBE_FINISHED_UNKNOWN,

[mmenke, 2013/06/28 20:43:27]

Think we should have a comment that the order of the completed status codes
matters for histograms, and other status codes must all appear first.

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+
+  // There's no internet connection.
+  DNS_PROBE_FINISHED_NO_INTERNET,
+
+  // The DNS configuration is wrong, or the servers are down or broken.
+  DNS_PROBE_FINISHED_BAD_CONFIG,
+
+  // The DNS servers are working fine, so the domain must not exist.
+  DNS_PROBE_FINISHED_NXDOMAIN,
+
   DNS_PROBE_MAX
 };
 
+const char* DnsProbeStatusToString(int status);
+bool DnsProbeStatusIsFinished(DnsProbeStatus status);
+
+bool DnsProbesEnabledByFieldTrial();
+
+extern const char kDnsProbeErrorDomain[];
+
 }  // namespace chrome_common_net
 
 #endif  // CHROME_COMMON_NET_NET_ERROR_INFO_H_