Revert "An RTCSessionDescription will now return nil from its initializer if the SDP passed to it is invalid."

This reverts commit 48cd9dbc5067f266b07541d2eebfb4b88fe455d4.

Reason for revert: Breaks downstream project.

Original change's description:
> An RTCSessionDescription will now return nil from its initializer if the SDP passed to it is invalid.
>
> Bug: webrtc:13022
> Change-Id: I2f2ad96884cf2f43f5ea95c1210470dd6aa5c919
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/226980
> Commit-Queue: Jake Bromberg <jakebromberg@google.com>
> Reviewed-by: Harald Alvestrand <hta@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#34607}

TBR=peah@webrtc.org,hta@webrtc.org,webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com,jakebromberg@google.com

Change-Id: Iee05f747e472208f8776944df15d9206485b167e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:13022
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/227341
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34615}

sdk/objc/api/peerconnection/RTCSessionDescription.h

@@ -36,10 +36,8 @@ RTC_OBJC_EXPORT
 
 - (instancetype)init NS_UNAVAILABLE;
 
-/** Initialize a session description with a type and SDP string. Returns nil if the sdp is invalid.
- */
-- (nullable instancetype)initWithType:(RTCSdpType)type
-                                  sdp:(NSString *)sdp NS_DESIGNATED_INITIALIZER;
+/** Initialize a session description with a type and SDP string. */
+- (instancetype)initWithType:(RTCSdpType)type sdp:(NSString *)sdp NS_DESIGNATED_INITIALIZER;
 
 + (NSString *)stringForType:(RTCSdpType)type;
 

sdk/objc/api/peerconnection/RTCSessionDescription.mm

@@ -17,45 +17,23 @@
 
 @implementation RTC_OBJC_TYPE (RTCSessionDescription)
 
-@synthesize nativeDescription = _nativeDescription;
 @synthesize type = _type;
 @synthesize sdp = _sdp;
 
 + (NSString *)stringForType:(RTCSdpType)type {
-  std::string string = [self stdStringForType:type];
+  std::string string = [[self class] stdStringForType:type];
   return [NSString stringForStdString:string];
 }
 
 + (RTCSdpType)typeForString:(NSString *)string {
   std::string typeString = string.stdString;
-  return [self typeForStdString:typeString];
+  return [[self class] typeForStdString:typeString];
 }
 
-+ (webrtc::SessionDescriptionInterface *)nativeDescriptionForString:(NSString *)sdp
-                                                               type:(RTCSdpType)type {
-  webrtc::SdpParseError error;
-
-  webrtc::SessionDescriptionInterface *description =
-      webrtc::CreateSessionDescription([self stdStringForType:type], sdp.stdString, &error);
-
-  if (!description) {
-    RTCLogError(@"Failed to create session description: %s\nline: %s",
-                error.description.c_str(),
-                error.line.c_str());
-  }
-
-  return description;
-}
-
-- (nullable instancetype)initWithType:(RTCSdpType)type sdp:(NSString *)sdp {
+- (instancetype)initWithType:(RTCSdpType)type sdp:(NSString *)sdp {
   if (self = [super init]) {
     _type = type;
     _sdp = [sdp copy];
-    _nativeDescription = [[self class] nativeDescriptionForString:_sdp type:_type];
-
-    if (_nativeDescription == nil) {
-      return nil;
-    }
   }
   return self;
 }
@@ -68,6 +46,23 @@
 
 #pragma mark - Private
 
+- (webrtc::SessionDescriptionInterface *)nativeDescription {
+  webrtc::SdpParseError error;
+
+  webrtc::SessionDescriptionInterface *description =
+      webrtc::CreateSessionDescription([[self class] stdStringForType:_type],
+                                       _sdp.stdString,
+                                       &error);
+
+  if (!description) {
+    RTCLogError(@"Failed to create session description: %s\nline: %s",
+                error.description.c_str(),
+                error.line.c_str());
+  }
+
+  return description;
+}
+
 - (instancetype)initWithNativeDescription:
     (const webrtc::SessionDescriptionInterface *)nativeDescription {
   NSParameterAssert(nativeDescription);

sdk/objc/unittests/RTCSessionDescriptionTest.mm

@@ -42,13 +42,6 @@
   EXPECT_EQ([self sdp].stdString, sdp);
 }
 
-- (void)testInvalidSessionDescriptionConversion {
-  RTC_OBJC_TYPE(RTCSessionDescription) *description =
-      [[RTC_OBJC_TYPE(RTCSessionDescription) alloc] initWithType:RTCSdpTypeAnswer sdp:@"invalid"];
-
-  EXPECT_EQ(nil, description);
-}
-
 - (void)testInitFromNativeSessionDescription {
   webrtc::SessionDescriptionInterface *nativeDescription;
 
@@ -142,13 +135,6 @@ TEST(RTCSessionDescriptionTest, SessionDescriptionConversionTest) {
   }
 }
 
-TEST(RTCSessionDescriptionTest, InvalidSessionDescriptionConversionTest) {
-  @autoreleasepool {
-    RTCSessionDescriptionTest *test = [[RTCSessionDescriptionTest alloc] init];
-    [test testInvalidSessionDescriptionConversion];
-  }
-}
-
 TEST(RTCSessionDescriptionTest, InitFromSessionDescriptionTest) {
   @autoreleasepool {
     RTCSessionDescriptionTest *test = [[RTCSessionDescriptionTest alloc] init];