System font check for downloadable font

Adds a new attribute to downloadable font xml
that checks if downloaded font is on the system
already and uses that instead.

Test: added new tests
Test: atest ResourcesTest
Test: atest FontResourcesParserTest

Bug: 178589784
Change-Id: Ib7c32ba3037c534e9ab8c144716d68e46c908a39
7 files changed