Histogram for UMA log upload connection type.

net/base/network_change_notifier.h

 // 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.
 
 #ifndef NET_BASE_NETWORK_CHANGE_NOTIFIER_H_
 #define NET_BASE_NETWORK_CHANGE_NOTIFIER_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 23 matching lines @@
 // and will be called back on the thread from which they registered.
 // NetworkChangeNotifiers are threadsafe, though they must be created and
 // destroyed on the same thread.
 class NET_EXPORT NetworkChangeNotifier {
  public:
   // This is a superset of the connection types in the NetInfo v3 specification:
   // http://w3c.github.io/netinfo/.
   //
   // A Java counterpart will be generated for this enum.
   // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.net
+  //
+  // Used to record the connection type used for uploading UMA logs in UMA

[pauljensen, 2015/03/26 19:03:35]

This is used for lots and lots of things, including surfacing to web pages via
netinfo.  This sentence makes it sounds like it's used just for UMA typing.  Can
we adjust this to be clearer, perhaps something like "New enum values should
only be added to the end of the enum and no values should be modified or reused,
as this is reported via UMA."

[gayane -on leave until 09-2017, 2015/03/26 19:09:05]

Done.

+  // histogram. Due to use in histogram this should be an append-only enum.
   enum ConnectionType {
     CONNECTION_UNKNOWN = 0,  // A connection exists, but its type is unknown.
                              // Also used as a default value.
     CONNECTION_ETHERNET = 1,
     CONNECTION_WIFI = 2,
     CONNECTION_2G = 3,
     CONNECTION_3G = 4,
     CONNECTION_4G = 5,
     CONNECTION_NONE = 6,     // No connection.
     CONNECTION_BLUETOOTH = 7,
@@ skipping 386 matching lines @@
 
   // Set true to disable non-test notifications (to prevent flakes in tests).
   bool test_notifications_only_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifier);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_NETWORK_CHANGE_NOTIFIER_H_