Revert "Add ios bindings for PeerConnectionState."

This reverts commit 586725dc9a508c7d3e82b5a625a5ee7e8b1a4e17.

Reason for revert: misses a check to see if the optional callback is implemented.

Original change's description:
> Add ios bindings for PeerConnectionState.
> 
> This change makes it possible for ios apps to use the new standards-compliant PeerConnectionState.
> 
> Bug: webrtc:9977
> Change-Id: Icf69bb1faa0383ae239cb7508f2a740a2d489697
> Reviewed-on: https://webrtc-review.googlesource.com/c/110502
> Commit-Queue: Jonas Olsson <jonasolsson@webrtc.org>
> Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#25651}

TBR=kthelgason@webrtc.org,jonasolsson@webrtc.org

Change-Id: Iff919e9876e6b8dddc6d8ab7df302081d0cfa917
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:9977
Reviewed-on: https://webrtc-review.googlesource.com/c/111062
Reviewed-by: Jonas Olsson <jonasolsson@webrtc.org>
Commit-Queue: Jonas Olsson <jonasolsson@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25659}
diff --git a/sdk/objc/api/peerconnection/RTCPeerConnection+Private.h b/sdk/objc/api/peerconnection/RTCPeerConnection+Private.h
index d26eb2e..b6440cd 100644
--- a/sdk/objc/api/peerconnection/RTCPeerConnection+Private.h
+++ b/sdk/objc/api/peerconnection/RTCPeerConnection+Private.h
@@ -39,8 +39,6 @@
 
   void OnIceConnectionChange(PeerConnectionInterface::IceConnectionState new_state) override;
 
-  void OnConnectionChange(PeerConnectionInterface::PeerConnectionState new_state) override;
-
   void OnIceGatheringChange(PeerConnectionInterface::IceGatheringState new_state) override;
 
   void OnIceCandidate(const IceCandidateInterface *candidate) override;
@@ -87,19 +85,11 @@
 + (webrtc::PeerConnectionInterface::IceConnectionState)nativeIceConnectionStateForState:
         (RTCIceConnectionState)state;
 
-+ (webrtc::PeerConnectionInterface::PeerConnectionState)nativeConnectionStateForState:
-        (RTCPeerConnectionState)state;
-
 + (RTCIceConnectionState)iceConnectionStateForNativeState:
         (webrtc::PeerConnectionInterface::IceConnectionState)nativeState;
 
-+ (RTCPeerConnectionState)connectionStateForNativeState:
-        (webrtc::PeerConnectionInterface::PeerConnectionState)nativeState;
-
 + (NSString *)stringForIceConnectionState:(RTCIceConnectionState)state;
 
-+ (NSString *)stringForConnectionState:(RTCPeerConnectionState)state;
-
 + (webrtc::PeerConnectionInterface::IceGatheringState)nativeIceGatheringStateForState:
         (RTCIceGatheringState)state;
 
diff --git a/sdk/objc/api/peerconnection/RTCPeerConnection.h b/sdk/objc/api/peerconnection/RTCPeerConnection.h
index 393a50b..0179ec0 100644
--- a/sdk/objc/api/peerconnection/RTCPeerConnection.h
+++ b/sdk/objc/api/peerconnection/RTCPeerConnection.h
@@ -57,16 +57,6 @@
   RTCIceConnectionStateCount,
 };
 
-/** Represents the combined ice+dtls connection state of the peer connection. */
-typedef NS_ENUM(NSInteger, RTCPeerConnectionState) {
-  RTCPeerConnectionStateNew,
-  RTCPeerConnectionStateConnecting,
-  RTCPeerConnectionStateConnected,
-  RTCPeerConnectionStateDisconnected,
-  RTCPeerConnectionStateFailed,
-  RTCPeerConnectionStateClosed,
-};
-
 /** Represents the ice gathering state of the peer connection. */
 typedef NS_ENUM(NSInteger, RTCIceGatheringState) {
   RTCIceGatheringStateNew,
@@ -125,14 +115,11 @@
  *  This is only called with RTCSdpSemanticsUnifiedPlan specified.
  */
 @optional
-/** Called any time the PeerConnectionState changes. */
-- (void)peerConnection:(RTCPeerConnection *)peerConnection
-    didChangeConnectionState:(RTCPeerConnectionState)newState;
-
 - (void)peerConnection:(RTCPeerConnection *)peerConnection
     didStartReceivingOnTransceiver:(RTCRtpTransceiver *)transceiver;
 
 /** Called when a receiver and its track are created. */
+@optional
 - (void)peerConnection:(RTCPeerConnection *)peerConnection
         didAddReceiver:(RTCRtpReceiver *)rtpReceiver
                streams:(NSArray<RTCMediaStream *> *)mediaStreams;
@@ -158,7 +145,6 @@
 @property(nonatomic, readonly, nullable) RTCSessionDescription *remoteDescription;
 @property(nonatomic, readonly) RTCSignalingState signalingState;
 @property(nonatomic, readonly) RTCIceConnectionState iceConnectionState;
-@property(nonatomic, readonly) RTCPeerConnectionState connectionState;
 @property(nonatomic, readonly) RTCIceGatheringState iceGatheringState;
 @property(nonatomic, readonly, copy) RTCConfiguration *configuration;
 
diff --git a/sdk/objc/api/peerconnection/RTCPeerConnection.mm b/sdk/objc/api/peerconnection/RTCPeerConnection.mm
index c19562b..1ac076b 100644
--- a/sdk/objc/api/peerconnection/RTCPeerConnection.mm
+++ b/sdk/objc/api/peerconnection/RTCPeerConnection.mm
@@ -175,14 +175,11 @@
 
 void PeerConnectionDelegateAdapter::OnIceConnectionChange(
     PeerConnectionInterface::IceConnectionState new_state) {
-  RTCIceConnectionState state = [RTCPeerConnection iceConnectionStateForNativeState:new_state];
-  [peer_connection_.delegate peerConnection:peer_connection_ didChangeIceConnectionState:state];
-}
-
-void PeerConnectionDelegateAdapter::OnConnectionChange(
-    PeerConnectionInterface::PeerConnectionState new_state) {
-  RTCPeerConnectionState state = [RTCPeerConnection connectionStateForNativeState:new_state];
-  [peer_connection_.delegate peerConnection:peer_connection_ didChangeConnectionState:state];
+  RTCIceConnectionState state =
+      [[RTCPeerConnection class] iceConnectionStateForNativeState:new_state];
+  RTCPeerConnection *peer_connection = peer_connection_;
+  [peer_connection.delegate peerConnection:peer_connection
+               didChangeIceConnectionState:state];
 }
 
 void PeerConnectionDelegateAdapter::OnIceGatheringChange(
@@ -325,10 +322,6 @@
       _peerConnection->ice_connection_state()];
 }
 
-- (RTCPeerConnectionState)connectionState {
-  return [[self class] connectionStateForNativeState:_peerConnection->peer_connection_state()];
-}
-
 - (RTCIceGatheringState)iceGatheringState {
   return [[self class] iceGatheringStateForNativeState:
       _peerConnection->ice_gathering_state()];
@@ -639,59 +632,6 @@
   }
 }
 
-+ (webrtc::PeerConnectionInterface::PeerConnectionState)nativeConnectionStateForState:
-        (RTCPeerConnectionState)state {
-  switch (state) {
-    case RTCPeerConnectionStateNew:
-      return webrtc::PeerConnectionInterface::PeerConnectionState::kNew;
-    case RTCPeerConnectionStateConnecting:
-      return webrtc::PeerConnectionInterface::PeerConnectionState::kConnecting;
-    case RTCPeerConnectionStateConnected:
-      return webrtc::PeerConnectionInterface::PeerConnectionState::kConnected;
-    case RTCPeerConnectionStateFailed:
-      return webrtc::PeerConnectionInterface::PeerConnectionState::kFailed;
-    case RTCPeerConnectionStateDisconnected:
-      return webrtc::PeerConnectionInterface::PeerConnectionState::kDisconnected;
-    case RTCPeerConnectionStateClosed:
-      return webrtc::PeerConnectionInterface::PeerConnectionState::kClosed;
-  }
-}
-
-+ (RTCPeerConnectionState)connectionStateForNativeState:
-        (webrtc::PeerConnectionInterface::PeerConnectionState)nativeState {
-  switch (nativeState) {
-    case webrtc::PeerConnectionInterface::PeerConnectionState::kNew:
-      return RTCPeerConnectionStateNew;
-    case webrtc::PeerConnectionInterface::PeerConnectionState::kConnecting:
-      return RTCPeerConnectionStateConnecting;
-    case webrtc::PeerConnectionInterface::PeerConnectionState::kConnected:
-      return RTCPeerConnectionStateConnected;
-    case webrtc::PeerConnectionInterface::PeerConnectionState::kFailed:
-      return RTCPeerConnectionStateFailed;
-    case webrtc::PeerConnectionInterface::PeerConnectionState::kDisconnected:
-      return RTCPeerConnectionStateDisconnected;
-    case webrtc::PeerConnectionInterface::PeerConnectionState::kClosed:
-      return RTCPeerConnectionStateClosed;
-  }
-}
-
-+ (NSString *)stringForConnectionState:(RTCPeerConnectionState)state {
-  switch (state) {
-    case RTCPeerConnectionStateNew:
-      return @"NEW";
-    case RTCPeerConnectionStateConnecting:
-      return @"CONNECTING";
-    case RTCPeerConnectionStateConnected:
-      return @"CONNECTED";
-    case RTCPeerConnectionStateFailed:
-      return @"FAILED";
-    case RTCPeerConnectionStateDisconnected:
-      return @"DISCONNECTED";
-    case RTCPeerConnectionStateClosed:
-      return @"CLOSED";
-  }
-}
-
 + (webrtc::PeerConnectionInterface::IceConnectionState)
     nativeIceConnectionStateForState:(RTCIceConnectionState)state {
   switch (state) {