Enable the public TTC index attribute for fonts

This change adds support for specifying the TTC index on font entries,
relevant in the context of .ttc font files used to deliver multiple
fonts in the same file.
Bug: 37853920
Test: adb shell am instrument -w -e class android.content.res.FontResourcesParserTest com.android.frameworks.coretests/android.support.test.runner.AndroidJUnitRunner

Change-Id: I3f74e87dec78e1f5a68ccead80b0f637af1aa7a3
9 files changed