This CL moves the implementations of the fake media engine from fakemediaengine.h to fakemediaengine.cc. Bug: webrtc:9883 Change-Id: I0f91ef63a366abe9638fc885bc14aba7dd5436aa Reviewed-on: https://webrtc-review.googlesource.com/c/106923 Reviewed-by: Niels Moller <nisse@webrtc.org> Commit-Queue: Sebastian Jansson <srte@webrtc.org> Cr-Commit-Position: refs/heads/master@{#25260}