Switch //components away from base::ListValue::Append(Value*) overload.

This overload is deprecated: prefer the std::unique_ptr<Value> version,
which helps the compiler enforce that ownership transfer occurs.

BUG=581865
R=danakj@chromium.org
TBR=blundell@chromium.org

Review-Url: https://codereview.chromium.org/2287733002
Cr-Commit-Position: refs/heads/master@{#414932}
32 files changed