Update usages of std::map to use ScopedPtrMap.

Almost all code that uses a std::map + STLValueDeleter has been modified
to use a ScopedPtrMap. This makes pointer ownership much clearer, and
removes a lot of manual pointer deletion.

BUG=478594

Review URL: https://codereview.chromium.org/1096983002

Cr-Commit-Position: refs/heads/master@{#336096}
50 files changed