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Currently ArcSupportHost is the ARC's implementation of
NativeMessageHost. Because of the system structure, the instance
is created and managed by the module outside of ARC.

This CL extracts the implementation of that part into
ArcSupportMessageHost so that the ArcSupportHost, which will
be the main interface to show UI things for ARC, can be managed
along with the ARC's life-time.

There is a plan to extract non authorization related part from
ArcAuthSerivce. Meanwhile, the instance is managed by
ArcAuthService, temporarily.

BUG=657687, 636218, 633258, b/31079732
TEST=Ran on test device. Ran trybots.

Review-Url: https://codereview.chromium.org/2436903003
Cr-Commit-Position: refs/heads/master@{#427277}