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.
+//
+// The DNS_PROBE_FINISHED_* values are used in histograms, so:
+// 1. FINISHED_UNKNOWN must remain the first FINISHED_* value.
+// 2. FINISHED_* values must not be rearranged relative to FINISHED_UNKNOWN.
+// 3. New FINISHED_* values must be inserted at the end.
+// 4. New non-FINISHED_* values must be inserted before FINISHED_UNKNOWN.
+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_INCONCLUSIVE,
+
+  // 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
 };
 
+// Returns a string representing |status|.  It should be simply the name of
+// the value as a string, but don't rely on that.  This is presented to the
+// user as part of the DNS error page (as the error code, at the bottom),
+// and is also used in some verbose log messages.
+//
+// |status| is an int because error codes are ints by the time they get to the
+// localized error system, and we don't want to require the caller to cast back
+// to a probe status.  The function will NOTREACHED() and return an empty
+// string if given an int that does not match a value in DnsProbeStatus (or if
+// it is DNS_PROBE_MAX, which is not a real status).
+const char* DnsProbeStatusToString(int status);
+
+// Returns true if |status| is one of the DNS_PROBE_FINISHED_* statuses.
+bool DnsProbeStatusIsFinished(DnsProbeStatus status);
+
+// Returns true if DNS probes are enabled (by the DnsProbe-Enable field trial),
+// or false if they are disabled or the field trial wasn't found.
+bool DnsProbesEnabledByFieldTrial();
+
+// The error domain used to pass DNS probe statuses to the localized error
+// code.
+extern const char kDnsProbeErrorDomain[];
+
 }  // namespace chrome_common_net
 
 #endif  // CHROME_COMMON_NET_NET_ERROR_INFO_H_