Pass platform configuration to Dart VM for insecure socket policy (flutter#20733)

Author: mehmetf

shell/platform/android/io/flutter/embedding/engine/loader/FlutterLoader.java

@@ -216,10 +216,9 @@ public void ensureInitializationComplete(
       }
 
       shellArgs.add("--cache-dir-path=" + result.engineCachesPath);
-      // TODO(mehmetf): Announce this since it is a breaking change then enable it.
-      // if (!flutterApplicationInfo.clearTextPermitted) {
-      //   shellArgs.add("--disallow-insecure-connections");
-      // }
+      if (!flutterApplicationInfo.clearTextPermitted) {
+        shellArgs.add("--disallow-insecure-connections");
+      }
       if (flutterApplicationInfo.domainNetworkPolicy != null) {
         shellArgs.add("--domain-network-policy=" + flutterApplicationInfo.domainNetworkPolicy);
       }

shell/platform/darwin/ios/framework/Source/FlutterDartProject.mm

@@ -140,12 +140,6 @@
   settings.domain_network_policy =
       [FlutterDartProject domainNetworkPolicy:appTransportSecurity].UTF8String;
 
-  // TODO(mehmetf): We need to announce this change since it is breaking.
-  // Remove these two lines after we announce and we know which release this is
-  // going to be part of.
-  settings.may_insecurely_connect_to_all_domains = true;
-  settings.domain_network_policy = "";
-
 #if FLUTTER_RUNTIME_MODE == FLUTTER_RUNTIME_MODE_DEBUG
   // There are no ownership concerns here as all mappings are owned by the
   // embedder and not the engine.