cc: Don't allocate 0-size discardable memory.
cc: Don't allocate 0-size discardable memory.

This patch ensures that when processing images we don't try to allocate
0 bytes of discardable memory. For now, allocate 1 byte with a TODO
to skip these images altogether.

R=enne
BUG=579498
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1633933002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#371413}

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