gn2bp: remove unused third_party deps handling

This was not useful for the cronet build, as we have not remapped
third_party deps into //gn (unlike perfetto).

We probably do want something similar for builtin_deps (like pass
builtin_deps into the GnParser constructor) to prevent static_library
dependencies to circumvent replaced dependencies via builtin_deps.

Test: //components/cronet/android:cronet
Change-Id: I77ed99eb14618a478281b9be025cf9d384066ddb
1 file changed