Mock more methods of dbus::Bus in dbus::MockBus.

This CL updates dbus::MockBus to mock dbus::Bus::AddFilterFunction and
dbus::Bus::RemoveFilterFunction. Neither method is exercised in existing
Chrome unit tests. However, some Chrome OS unit tests (e.g. CL:1048028)
need to mock them, which is currently done by sub-classing
dbus::MockBus. This CL alleviates the need of such sub-classing.

Bug: None
Change-Id: Ib5f3e41573ec900351ebedad030bb6147db3b74f
Reviewed-on: https://chromium-review.googlesource.com/1054159Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557811}

dbus/mock_bus.h

@@ -48,10 +48,12 @@ class MockBus : public Bus {
                                    DBusPendingCall** pending_call,
                                    int timeout_ms));
   MOCK_METHOD2(Send, void(DBusMessage* request, uint32_t* serial));
-  MOCK_METHOD2(AddFilter, void(DBusHandleMessageFunction handle_message,
-                               void* user_data));
-  MOCK_METHOD2(RemoveFilter, void(DBusHandleMessageFunction handle_message,
-                                  void* user_data));
+  MOCK_METHOD2(AddFilterFunction,
+               void(DBusHandleMessageFunction filter_function,
+                    void* user_data));
+  MOCK_METHOD2(RemoveFilterFunction,
+               void(DBusHandleMessageFunction filter_function,
+                    void* user_data));
   MOCK_METHOD2(AddMatch, void(const std::string& match_rule,
                               DBusError* error));
   MOCK_METHOD2(RemoveMatch, bool(const std::string& match_rule,