Remove ListValue::Append(raw ptr) on Mac and iOS

ListValue::Append(raw ptr) is deprecated and the unique_ptr version should be
used instead. This CL achieves that on Mac and iOS specifically.

The CL also changes some related calls to DictionaryValue::Set to take
a unique_ptr instead of a raw one.

BUG=581865

Review-Url: https://codereview.chromium.org/2817603003
Cr-Commit-Position: refs/heads/master@{#464862}
11 files changed