Use rtc::saturated_cast instead of static_cast in VCMFecMethod
Use rtc::saturated_cast instead of static_cast in VCMFecMethod

Bug: webrtc:9439
Change-Id: Ia76a37ab5ae4871c7437b1b4c242556cd33bee40
Reviewed-on: https://webrtc-review.googlesource.com/92701
Reviewed-by: Erik Språng <3ab8c90c99d6dd7822e0fad803ab0211dd287ae5@webrtc.org>
Commit-Queue: Emircan Uysaler <4f4cc7487b5e739a8a7d6463b8e18c84b5876be1@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#24214}
TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc