[generator] Add more [ObsoleteOSPlatform] to prevent CA1422 (#1078)

Context: dotnet/android#7590
Context: dotnet/android@7004467
While building `Mono.Android.dll`, we had 1462 `CA1422` warnings of the
following caused by an interface being marked as `[ObsoleteOSPlatform]`
but the interface invoker class is not similarly annotated:
…\xamarin-android\src\Mono.Android\obj\Debug\net8.0\android-33\mcw\Org.Apache.Commons.Logging.ILog.cs(128,11): warning CA1422: This call site is reachable on: 'Android' 21.0 and later.
'ILog' is obsoleted on: 'Android' 22.0 and later (This class is obsoleted in this android platform).
There were also 42 `CA1422` warnings caused by interface async
extension classes not having `[ObsoleteOSPlatform]` attributes:
…\xamarin-android\src\Mono.Android\obj\Debug\net8.0\android-33\mcw\Org.Apache.Http.IO.ISessionOutputBuffer.cs(52,58):
warning CA1422: This call site is reachable on: 'Android' 21.0 and later.
'ISessionOutputBuffer.Write(byte[]?, int, int)' is obsoleted on: 'Android' 22.0 and later (This class is obsoleted in this android platform).
These warnings were disabled in dotnet/android@70044670.
Fix these warnings by adding the `[ObsoleteOSPlatform]` attribute to
these types if the source interface is deprecated.

Author: jpobst

tests/generator-Tests/Unit-Tests/CodeGeneratorTests.cs

@@ -611,6 +611,36 @@ public void ObsoletedOSPlatformAttributeUnneededSupport ()
 Assert.True(writer.ToString().Contains("[global::System.Obsolete (@\"This method has an invalid deprecated-since!\")]"),writer.ToString());
 }
 
+[Test]
+publicvoidObsoletedOSPlatformAttributeInterfaceInfrastructureSupport()
+{
+varxml=@"<api>
+ <package name='com.xamarin.android' jni-name='com/xamarin/android'>
+ <interface abstract='false' deprecated='This interface was deprecated in API-25' final='false' name='MyType' static='false' visibility='public' jni-signature='Lcom/xamarin/android/MyType;' deprecated-since='25' />
+ </package>
+ </api>";
+
+options.UseObsoletedOSPlatformAttributes=true;
+
+vargens=ParseApiDefinition(xml);
+variface=gens.OfType<InterfaceGen>().Single(g =>g.Name=="IMyType");
+
+generator.Context.ContextTypes.Push(iface);
+varinvoker=newInterfaceInvokerClass(iface,options,generator.Context);
+varextensions=newInterfaceExtensionsClass(iface,iface.Name,options);
+generator.Context.ContextTypes.Pop();
+
+// Ensure attribute was added to invoker class
+varinvoker_attribute=invoker.Attributes.OfType<ObsoletedOSPlatformAttr>().Single();
+Assert.AreEqual("This interface was deprecated in API-25",invoker_attribute.Message);
+Assert.AreEqual(25,invoker_attribute.Version);
+
+// Ensure attribute was added to extensions class
+varextensions_attribute=invoker.Attributes.OfType<ObsoletedOSPlatformAttr>().Single();
+Assert.AreEqual("This interface was deprecated in API-25",extensions_attribute.Message);
+Assert.AreEqual(25,extensions_attribute.Version);
+}
+
 [Test]
 publicvoidObsoleteGetterOnlyProperty()
 {

tools/generator/SourceWriters/InterfaceExtensionsClass.cs

@@ -18,6 +18,8 @@ public InterfaceExtensionsClass (InterfaceGen iface, string declaringTypeName, C
 IsStatic=true;
 IsPartial=true;
 
+SourceWriterExtensions.AddObsolete(Attributes,iface.DeprecatedComment,opt,iface.IsDeprecated,deprecatedSince:iface.DeprecatedSince);
+
 foreach(varmethodiniface.Methods.Where(m =>!m.IsStatic)){
 if(method.CanHaveStringOverload){
 // TODO: Don't allow obsolete here to match old generator.

tools/generator/SourceWriters/InterfaceInvokerClass.cs

@@ -32,6 +32,8 @@ public InterfaceInvokerClass (InterfaceGen iface, CodeGenerationOptions opt, Cod
 MemberType=(!ji)?null:(MemberTypes?)MemberTypes.TypeInfo,
 });
 
+SourceWriterExtensions.AddObsolete(Attributes,iface.DeprecatedComment,opt,iface.IsDeprecated,deprecatedSince:iface.DeprecatedSince);
+
 Fields.Add(newPeerMembersField(opt,iface.RawJniName,$"{iface.Name}Invoker",false));
 
 if(!ji){