Introduce parser and trace type for searches.

Extract trace processor initialization as the same instance created and
used in Perfetto ParserFactory must be accessible from the mediator to
create new search traces when queries are run from the viewer page.

Bug: 311643446
Test: npm run test:unit:ci
Change-Id: I038aa2c7b7ae0378f7bcf2f1f3bab1ab093e2db1
6 files changed