Preparation for deleting VCMEncodedFrame::VerifyAndAllocate and EncodedImage::Allocate. Bug: webrtc:9378 Change-Id: If7c16061962bbd58c3e7d5720189854e00a3d7bf Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/154570 Reviewed-by: Philip Eliasson <philipel@webrtc.org> Commit-Queue: Niels Moller <nisse@webrtc.org> Cr-Commit-Position: refs/heads/master@{#29339}