Usage of Chromium's lldbinit.py is recommended when debugging with lldb. This is necessary for source-level debugging when strip_absolute_paths_from_debug_symbols is enabled [this is the default].
To use, add the following to your ~/.lldbinit
# So that lldbinit.py takes precedence. script sys.path[:0] = ['<.../path/to/chromium/src/tools/lldb>'] script import lldbinit