Merge pull request #3260 from square/fix_missing_proto_message_conformance

[swift] Fix conformance to ProtoMessage for heap allocated protos

Author: dnkoutso

wire-swift-generator/src/main/java/com/squareup/wire/swift/SwiftGenerator.kt

@@ -461,6 +461,11 @@ class SwiftGenerator private constructor(
         .build()
       fileMembers += FileMemberSpec.builder(structProtoCodableExtension).build()
 
+      val structMessageConformanceExtension = ExtensionSpec.builder(structType)
+        .messageConformanceExtension(type)
+        .build()
+      fileMembers += FileMemberSpec.builder(structMessageConformanceExtension).build()
+
       val structCodableExtension = heapCodableExtension(structType, storageName, storageType)
       fileMembers += FileMemberSpec.builder(structCodableExtension)
         .addGuard("!$FLAG_REMOVE_CODABLE")

wire-tests-swift/no-manifest/src/main/swift/AllTypes.swift

@@ -1911,6 +1911,14 @@ extension AllTypes : Proto2Codable {
 
 }
 
+extension AllTypes : ProtoMessage {
+
+    public static func protoMessageTypeURL() -> String {
+        return "type.googleapis.com/squareup.protos.kotlin.alltypes.AllTypes"
+    }
+
+}
+
 #if !WIRE_REMOVE_CODABLE
 extension AllTypes : Codable {