Revert "Add a flag to actively reset the SRTP parameters"

This reverts commit bae103126c5bdaf1361bcff4750eb5ebe10020ee.

Reason for revert: Merge native code change with Android and Objc wrapper.

Original change's description:
> Add a flag to actively reset the SRTP parameters
> 
> Add a new flag to RtcConfiguration. By setting that flag to true, the
> SRTP parameters will be reset whenever the DTLS transports are reset
> after every offer/answer negotiation.
> 
> This should only be used as a workaround for the linked bug, if the
> application knows that the other party is affected (for instance,
> using a version number).
> 
> Bug: chromium:835958
> Change-Id: Ifb4b99f68dc272507728ab59c07627f0d1b9c605
> Reviewed-on: https://webrtc-review.googlesource.com/81642
> Commit-Queue: Zhi Huang <zhihuang@webrtc.org>
> Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#23570}

TBR=deadbeef@webrtc.org,zhihuang@webrtc.org

Change-Id: Ibd7a3b8f45ff8df4af33d758f8fd3e2d5158e8e2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:835958
Reviewed-on: https://webrtc-review.googlesource.com/83080
Reviewed-by: Zhi Huang <zhihuang@webrtc.org>
Commit-Queue: Zhi Huang <zhihuang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23571}

api/peerconnectioninterface.h

@@ -577,13 +577,6 @@ class PeerConnectionInterface : public rtc::RefCountInterface {
     // For all other users, specify kUnifiedPlan.
     SdpSemantics sdp_semantics = SdpSemantics::kPlanB;
 
-    // Actively reset the SRTP parameters whenever the DTLS transports
-    // underneath are reset for every offer/answer negotiation.
-    // This is only intended to be a workaround for crbug.com/835958
-    // WARNING: This would cause RTP/RTCP packets decryption failure if not used
-    // correctly. This flag will be deprecated soon. Do not rely on it.
-    bool active_reset_srtp_params = false;
-
     //
     // Don't forget to update operator== if adding something.
     //