debug-viewer: Fix C++ detection of lambdas as function

https://bugzilla.gnome.org/show_bug.cgi?id=793422

debug-viewer/GstDebugViewer/Data.py

@@ -155,7 +155,7 @@ def default_log_line_regex_():
     PID = r"(\d+)\s*"
     FILENAME = r"([^:]*):"
     LINE = r"(\d+):"
-    FUNCTION = "([A-Za-z0-9_]*):"
+    FUNCTION = "([A-Za-z0-9_]*|operator\(\)):"
     # FIXME: When non-g(st)object stuff is logged with *_OBJECT (like
     # buffers!), the address is printed *without* <> brackets!
     OBJECT = "(?:<([^>]+)>)?"