Each byte is converted to float (0.0 to 255.0) and then multiplied
by a scale parameter.

Bug: None
Test: arm 64 build passes.
Change-Id: I04736798540b8d985f60abdf0388e24a209d075b
Reviewed-on: https://chromium-review.googlesource.com/930226
Commit-Queue: Frank Barchard <fbarchard@chromium.org>
Reviewed-by: Ian Field <ianfield@google.com>