For Flutter docs, be more aggressive about including dependencies

[Hixie]

Right now we don't export all of vector_math in the Flutter docs, but we do export Matrix4. This results in Matrix4 being documented, but the types that it uses not being documented.

We should, IMHO, have a way to tell dartdoc that we want to include the documents for all our dependencies, with dartdoc automatically following the imports to find everything that's mentioned and documenting them all.

See also:

• In Flutter docs, classes are listed multiple times #1158 (about not including reexported types twice)

cc @devoncarew

[astashov]

I will look at it

[astashov]

So, how will it look like? We provide additional argument to the dartdoc script, like dartdoc --include-all-dependencies, and it will first go through all the dependencies we tell it to document (i.e. libs of the current package + all the --include-externals), and if it finds some symbols from some libraries are undocumented, it will add those libraries to the list of documentable libs? Something like that?

[Hixie]

Sounds good to me.