add cache_read metric definition

Add Cobalt definition for the cache_read metric for FTS.

Bug: 41857
Test: fx build
Change-Id: If7795c2880901381ce7eeeaa1c27ecbd0ccae0f6
1 file changed
tree: 1e2372246864f857b1a44324256d8e57cd257939
  1. cobalt_internal/
  2. fuchsia/
  3. .gitignore
  4. BUILD.gn
  5. check.py
  6. OWNERS
  7. projects.yaml