The cricket::Codec class contains std containers like
std::map<std::string, std::string> and is expensive to copy. This CL
adds move constructors and move assignment operators for it and all
subclasses.
This CL also:
* Implement functions with '= default' instead of doing it manually.
* Makes codec::Matches symmetric. We currently don't check if the
payload type of the callee is static, and might incorrectly return
true in these cases.
BUG=None
Review-Url: https://codereview.webrtc.org/2481193002
Cr-Commit-Position: refs/heads/master@{#14956}
3663c52382