watchable store: extract func that gets next log seq

Extracting the function that returns the next sequence number to be
used for a new commit. The function is optimized with a binary search.
The same function will be used to implement the GetResumeMarker().

Change-Id: I89fd5899f82e0e25e666873ee8a79a1d095e82bb
4 files changed
tree: 889c8e0836fc491aabc1824e0ed7c20ea730e9c1
  1. v23/
  2. x/
  3. .gitignore
  4. AUTHORS
  5. CONTRIBUTORS
  6. LICENSE
  7. PATENTS
  8. VERSION