BUG=129

Change-Id: I4a501fa620b7b5b4c585731ec1ece94407e9b727
Reviewed-on: https://boringssl-review.googlesource.com/16510
Reviewed-by: Adam Langley <agl@google.com>

These structures allow for blobs of data (e.g. certificates) to be
deduplicated in memory.

Change-Id: Iebfec90b85d55565848a178b6951562b4ccc083e
Reviewed-on: https://boringssl-review.googlesource.com/11820
Reviewed-by: Adam Langley <alangley@gmail.com>
Commit-Queue: Adam Langley <alangley@gmail.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>