Add IPC message definitions for camera
Add IPC message definitions for camera

This code will be shared between ChromeOS and ARC, and will
allow them to communicate with each other.

BUG=b:25054142

Review URL: https://codereview.chromium.org/1521383002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#365174}

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