Move public headers in WebKit/common to WebKit/public/common (2)

Moves:
- client_hints/client_hints.h
- device_memory/approximated_device_memory.h
- feature_policy/feature_policy.h
- message_port/message_port_channel.h
- message_port/cloneable_message.h
- message_port/transferable_message.h

R=haraken@chromium.org,jam@chromium.org

Bug: 809983
Change-Id: I5bde75652c26f3fdfc0f48ceb242aaa5c4cf7272
Reviewed-on: https://chromium-review.googlesource.com/910733
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#535933}
85 files changed