Remove base::Value::CreateNullValue

This change removes base::Value::CreateNullValue in favor of Value's default constructor. In particular, this change

- Replaces |Value::CreateNullValue()| with |MakeUnique<Value>()|.
  - Adds #includes of base/memory/ptr_util.h where needed.
  - Replaces |std::unique_ptr<Value>| with |auto| where appropriate.
- Replaces |*Value::CreateNullValue()| with |Value()|.
- Replaces |Value::CreateNullValue().release()| with |new Value()|.

BUG=646113
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2792573002
Cr-Commit-Position: refs/heads/master@{#462794}


CrOS-Libchrome-Original-Commit: e067999ab52ac73c13981b100f3ebcf9c62ef817
16 files changed
tree: 302ace8792690d92ecc6fd84ff8ee11e4f0483d3
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/