In ShillClientHelper use a{sv} for property dictionaries

chromeos/dbus/shill_client_helper.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 CHROMEOS_DBUS_SHILL_CLIENT_HELPER_H_
 #define CHROMEOS_DBUS_SHILL_CLIENT_HELPER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 123 matching lines @@
       const ErrorCallback& error_callback);
 
   // Calls a method with a boolean array result with error callback.
   void CallListValueMethodWithErrorCallback(
       dbus::MethodCall* method_call,
       const ListValueCallback& callback,
       const ErrorCallback& error_callback);
 
   const dbus::ObjectProxy* object_proxy() const { return proxy_; }
 
-  // Appends the value (basic types and string-to-string dictionary) to the
-  // writer as a variant.
+  // Appends the value to the writer as a variant. If |value| is a Dictionary it
+  // will be written as a string -> varient dictionary, a{sv}. If |value| is a
+  // List then it must be a List of String values and is writen as type 'as'.
   static void AppendValueDataAsVariant(dbus::MessageWriter* writer,
                                        const base::Value& value);
 
-  // Appends a string-to-variant dictionary to the writer.
-  static void AppendServicePropertiesDictionary(
-      dbus::MessageWriter* writer,
-      const base::DictionaryValue& dictionary);
+  // As above but if |use_string_dictionaries| is true and |value| is a
+  // Dictionary then it will be wtitten as type 'a{ss}'. (This is to support
+  // Cellular.APN which expects a string -> string dictionary).
+  static void AppendValueDataAsVariantEx(dbus::MessageWriter* writer,
+                                         const base::Value& value,
+                                         bool use_string_dictionaries);
+
+  // Appends a string-to-variant dictionary to the writer as an '{sv}' array.
+  // Each value is written using AppendValueDataAsVariant.
+  static void AppendServicePropertiesDictionary(dbus::MessageWriter* writer,
+                                                const base::DictionaryValue&);
 
  protected:
   // Reference / Ownership management. If the number of active refs (observers
   // + in-progress method calls) becomes 0, |released_callback_| (if set) will
   // be called.
   void AddRef();
   void Release();
 
  private:
   // Starts monitoring PropertyChanged signal.
@@ skipping 18 matching lines @@
   // Note: This should remain the last member so it'll be destroyed and
   // invalidate its weak pointers before any other members are destroyed.
   base::WeakPtrFactory<ShillClientHelper> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ShillClientHelper);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_SHILL_CLIENT_HELPER_H_