How to trace gyp?

https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/chromium-dev/vWMF_heQ2s0

[3680b9e...]d:\src\cr\src>set GYP_GENERATORS=dump_dependency_json

[3680b9e...]d:\src\cr\src>python build\gyp_chromium

Updating projects from gyp files...

Wrote json to dump.json.

[3680b9e...]d:\src\cr\src>python tools\gyp-explain.py views_examples_with_content_exe ash.gyp:ash#target

These paths lead from d:\src\cr\src\ui\views\views.gyp:views_examples_with_content_exe#target to d:\src\cr\src\ash\ash.gyp:ash#target:

d:\src\cr\src\ui\views\views.gyp:views_examples_with_content_exe#target -> d:\src\cr\src\content\content_shell_and_tests.gyp:content_shell_lib#target -> d:\src\cr\src\ash\ash.gyp:ash#target