authfs: refine/rename trait ReadOnlyDataByChunk

 - ReadOnlyDataByChunk is renamed to ReadByChunk
 - `fn read_chunk` now takes a fixed-size array of chunk size
 - Behavior change:
   1. Reading beyond file size now should not crash, and should return 0.
   2. `read_chunk` should return a full chunk unless it's the last
      (wasn't clearly defined previously).

Bug: 181674212
Bug: 182173887
Test: atest

Change-Id: I7017b5ed986d0bfc594da58a1ed9f59ac555643e
6 files changed
tree: 47fb09c127abe875ceaf53a8630ad311e296e7d2
  1. apex/
  2. authfs/
  3. docs/
  4. microdroid/
  5. tests/
  6. virtmanager/
  7. vm/
  8. .clang-format
  9. PREUPLOAD.cfg