AIDEGen: Collect dependencies info from APEX module.

Add apex dependencies.

Bug: 188004865
Test: 1. aidegen frameworks/base/apex/appsearch frameworks/base/apex/appsearch/testing   frameworks/base/services/tests/servicestests   frameworks/base/core/tests/coretests   cts/tests/appsearch   external/icing   vendor/google_testing/integration/tests/scenarios
      2. The dependency graph shows it is workable to provide the result to let IDE's [Project structure] to include the service-appsearch as source directory.
Change-Id: Ifd1548f0a86c1c73f8279e8ecea67756aeb1281e