[mojo-edk] Add sanity checks to NodeChannel inputs
[mojo-edk] Add sanity checks to NodeChannel inputs

Prevents reading memory beyond the bounds of a
received NodeChannel message.

BUG=611887

Review-Url: https://codereview.chromium.org/1977493004
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#393713}

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