Make sure the resulted operation is calculated on float basis.

BUG=webrtc:7558

Review-Url: https://codereview.webrtc.org/2634283002
Cr-Original-Commit-Position: refs/heads/master@{#17983}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 4ed18da9903f6fdb4a502def3e0e6f0408463940
1 file changed