This commit changes modify_parsed_flags_based_on_mode to return Result
instead of vector. This change will have two consequences.
1. Error will be thrown if no flags fit into the current codegen mode
2. Error will be thrown if the flag declaration is empty
Bug: 311152507
Test: atest aconfig.test
Change-Id: I69b9a84312faed9f757bf3974b3cea49c5c5e285
Consolidate the code generation sources into its own module. This is
done in preparation for when support for the new flag storage will be
added, which should also be placed in a separate module.
Bug: N/A
Test: atest aconfig.test aconfig.test.java
Change-Id: I8246729218ec60f2af4568c460e98329665a89fa