logd: statistics switch to std::string

(cherry pick from commit 09a91e22b361bbfcd9283f26ac08714085f07b56)

Bug: 23350706
Change-Id: I5564898c4f67b8fcc43cee64604855f789409482
2 files changed
tree: e087ed0c763b35d8071dcc2319c839c876f017a9
  1. liblog/
  2. logcat/
  3. logd/
  4. logwrapper/