Minor SimpleCacheBackend improvements.

- Use a base::hash_map instead of a std::map for the
  SimpleBackendImpl::EntryMap type, to reduce heap usage.

  This saves 3 pointers/node on Android, since there is no
  need for an ordered map here.

- Avoid creating a new closure on every call to
  SimpleIndex::PostponeWritingToDisk. Each base::Bind() call
  creates a new heap-allocated reference-counted object.

  Given that this function is called for every mutating
  operation on the index, it's a good idea to get rid of it.

  Since the called function and its argument never change,
  create the closure only once and reuse it on every
  write_to_disk_timer_.Start() call.

- Avoid performing one extra lookup and one extra call
  to PostponeWritingToDisk() in SimpleIndex::Remove().

- Remove un-necessary temporary string creations and a tiny
  typo.

R=felipeg@chromium.org, gavinp@chromium.org, pasko@chromium.org, pliard@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/14877019

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@204035 0039d316-1c4b-4281-b951-d872f2087c98

0 files changed, 0 insertions, 0 deletions