New versions of Closure Compiler upgraded "module not found" from warnings to errors. For example:

!../model/doc.Doc doesn't exist in the bundled SWG binary.

Unfortunately don't seem suppressible with @suppress {moduleLoad}, individually or at the @fileoverview level. The current workaround is to not fail the build on warnings in swg.js replace these types with * via regex (see #18589).

To fix this, we can either strip these bogus types, use externs, or bundle these missing classes.

Context: #18552

/to @jpettit /cc @dvoytenko @dparikh