Port c343f309

Original commit message:
    This operator now provides a second output which indicates whether the
    conversion from float64 to uint64 was successful or not. The second output
    returns 0 if the conversion fails, or something else if the conversion
    succeeds.

    The second output can be ignored, which means that the operator can be used
    the same as the original operator.

R=ahaas@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1512963002

Cr-Commit-Position: refs/heads/master@{#32728}