Remove DCHECK from common_types.cc
Remove DCHECK from common_types.cc

The DCHECKs added in https://webrtc-codereview.appspot.com/41069004/
introduces a dependency on base, which may cause problems.
This CL reverts that change.

R=tommi@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/48389004

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#8602}
git-svn-id: 917f5d3ca488f358c4d40eaec14422cf392ccec9@8602 4adac7df-926f-26a2-2b94-8c16560cd09d

TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc