tree 8880a67817048491a8091c5cf7e97f1cf21218ba
parent ffae101c755d283919d6c15f1336cbc8fb724ac3
author Sameer Agarwal <sameeragarwal@google.com> 1522386089 -0700
committer Sameer Agarwal <sameeragarwal@google.com> 1522436608 -0700

More C++11ification.

1. Replace HashMap and HashSet with std::unordered_map and
   std::unordered_set respectively.
2. Extract the pair hasher into a struct pair_hash.
3. Delete collections_port.h
4. Convert explicit iterator based loops to auto based
   loops where sensible.

Change-Id: Ib88bcd13a7463d18435639d3b771abaa52080efb