[illink] Redo Java.Lang.Object serialization

[radekdoulik]

Context: #5454

The use of DataContract attribute on Java.Lang.Object class pulls
in System.Runtime.Serialization.Primitives assembly.

We still need to make the Java.Lang.Object class serializable, so that
inherited types can be serialized. Otherwise that would lead to
System.Runtime.Serialization.InvalidDataContractException during
runtime.

Instead of decorating Java.Lang.Object with DataContract attribute,
use Serializable attribute on class and NonSerialized attribute on fields.

This might seem contraproductive, to use multiple attribute instances
instead of one. In real it is not and leads to size saving and getting rid
of System.Runtime.Serialization.Primitives assembly reference
in linked apps. Because the Serializable and NonSerialized attributes
are not present in the compiled output, instead flags are used.

The compiled Java.Lang.Object class IL looks like this:

.class public auto ansi serializable beforefieldinit Java.Lang.Object
       extends [System.Private.CoreLib]System.Object
       implements [System.Private.CoreLib]System.IDisposable,
                  Android.Runtime.IJavaObject,
                  Java.Interop.IJavaObjectEx,
                  [Java.Interop]Java.Interop.IJavaPeerable
{
  .custom instance void Android.Runtime.RegisterAttribute::.ctor(string) = ( 01 00 10 6A 61 76 61 2F 6C 61 6E 67 2F 4F 62 6A   // ...java/lang/Obj
                                                                             65 63 74 01 00 54 02 10 44 6F 4E 6F 74 47 65 6E   // ect..T..DoNotGen
                                                                             65 72 61 74 65 41 63 77 01 )                      // erateAcw.
  .field private static initonly class [Java.Interop]Java.Interop.JniPeerMembers _members
  .field private static class [System.Private.CoreLib]System.Delegate cb_equals_Ljava_lang_Object_
  .field private static class [System.Private.CoreLib]System.Delegate cb_hashCode
  .field private static class [System.Private.CoreLib]System.Delegate cb_toString
  .field private notserialized native int key_handle
  .field private notserialized native int weak_handle
  .field private notserialized int32 refs_added
  .field private notserialized valuetype Android.Runtime.JObjectRefType handle_type
  .field private notserialized native int handle
  .field private notserialized bool needsActivation
  .field private notserialized bool isProxy
...

The apk size savings on net6 in BuildReleaseArm64False test:

> apkdiff -md -e dll$ before.apk after.apk
Size difference in bytes ([*1] apk1 only, [*2] apk2 only):
  -          13 assemblies/Mono.Android.dll
    -         120 Metadata
      -          60 Stream #~ (tables)
        -           6 Table TypeRef
        -           6 Table MemberRef
        -           6 Table CustomAttribute
        -          40 Table AssemblyRef
      -          60 Stream #Strings
    Type Java.Lang.Object
      -             CustomAttribute System.Runtime.Serialization.DataContractAttribute
  -       2,583 assemblies/System.Runtime.Serialization.Primitives.dll *1
Summary:
  -       2,596 Assemblies -0.28% (of 915,384)

I have also added a new test for Java.Lang.Object class serialization with code from
old Hello sample.

Example of System.Runtime.Serialization.InvalidDataContractException during runtime,
if Java.Lang.Object class was not serializable:

I MonoDroid: Android.Runtime.JavaProxyThrowable: Exception of type 'Android.Runtime.JavaProxyThrowable' was thrown.
I MonoDroid:   --- End of managed Android.Runtime.JavaProxyThrowable stack trace ---
I MonoDroid: android.runtime.JavaProxyThrowable: System.Runtime.Serialization.InvalidDataContractException: Type 'UnnamedProject.Person' cannot inherit from a type that is not marked with DataContractAttribute or SerializableAttribute.  Consider marking the base type 'Java.Lang.Object' with DataContractAttribute or SerializableAttribute, or removing them from the derived type.
I MonoDroid:   at System.Runtime.Serialization.ClassDataContract+ClassDataContractCriticalHelper..ctor (System.Type type) [0x001c3] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.ClassDataContract..ctor (System.Type type) [0x00000] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.DataContract+DataContractCriticalHelper.CreateDataContract (System.Int32 id, System.RuntimeTypeHandle typeHandle, System.Type type) [0x000e0] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.DataContract+DataContractCriticalHelper.GetDataContractSkipValidation (System.Int32 id, System.RuntimeTypeHandle typeHandle, System.Type type) [0x0000b] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.DataContract.GetDataContractSkipValidation (System.Int32 id, System.RuntimeTypeHandle typeHandle, System.Type type) [0x00000] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.DataContract.GetDataContract (System.Int32 id, System.RuntimeTypeHandle typeHandle, System.Runtime.Serialization.SerializationMode mode) [0x00000] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.DataContract.GetDataContract (System.RuntimeTypeHandle typeHandle, System.Type type, System.Runtime.Serialization.SerializationMode mode) [0x00006] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.DataContract.GetDataContract (System.Type type) [0x00006] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.Json.DataContractJsonSerializer.get_RootContract () [0x00022] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.Json.DataContractJsonSerializer.InternalWriteObjectContent (System.Runtime.Serialization.XmlWriterDelegator writer, System.Object graph) [0x00031] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.Json.DataContractJsonSerializer.InternalWriteObject (System.Runtime.Serialization.XmlWriterDelegator writer, System.Object graph) [0x00008] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.XmlObjectSerializer.InternalWriteObject (System.Runtime.Serialization.XmlWriterDelegator writer, System.Object graph, System.Runtime.Serialization.DataContractResolver dataContractResolver) [0x00000] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.XmlObjectSerializer.WriteObjectHandleExceptions (System.Runtime.Serialization.XmlWriterDelegator writer, System.Object graph, System.Runtime.Serialization.DataContractResolver dataContractResolver) [0x00073] in <686be187480b41979dcbf5635f805a7b>:0 01-07 16:13:09.246 10624 10624 I MonoDroid:   at System.Runtime.Serialization.XmlObjectSerializer.WriteObjectHandleExceptions (System.Runtime.Serialization.XmlWriterDelegator writer, System.Object graph) [0x00000] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.Json.DataContractJsonSerializer.WriteObject (System.Xml.XmlDictionaryWriter writer, System.Object graph) [0x0000d] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at System.Runtime.Serialization.Json.DataContractJsonSerializer.WriteObject (System.IO.Stream stream, System.Object graph) [0x00018] in <686be187480b41979dcbf5635f805a7b>:0
I MonoDroid:   at UnnamedProject.MainActivity.TestJsonDeserializationCreatesJavaHandle () [0x00033] in <11a2c65ab60d41dea720c7638d552ce0>:0
I MonoDroid:   at UnnamedProject.MainActivity.OnCreate (Android.OS.Bundle bundle) [0x0004b] in <11a2c65ab60d41dea720c7638d552ce0>:0 01-07 16:13:09.247 10624 10624 I MonoDroid:   at Android.App.Activity.n_OnCreate_Landroid_os_Bundle_ (System.IntPtr jnienv, System.IntPtr native__this, System.IntPtr native_savedInstanceState) [0x00012] in <3045e86f0ced43c19ee1b522f77c72d7>:0
I MonoDroid:   at Android.App.Activity.n_OnCreate_Landroid_os_Bundle_ (System.IntPtr jnienv, System.IntPtr native__this, System.IntPtr native_savedInstanceState) [0x00012] in <3045e86f0ced43c19ee1b522f77c72d7>:0
I MonoDroid:   at (wrapper dynamic-method) Android.Runtime.DynamicMethodNameCounter.1(intptr,intptr,intptr)
I MonoDroid:     at unnamedproject.unnamedproject.MainActivity.n_onCreate(Native Method)
I MonoDroid:     at unnamedproject.unnamedproject.MainActivity.onCreate(MainActivity.java:29)
I MonoDroid:     at android.app.Activity.performCreate(Activity.java:8000)
I MonoDroid:     at android.app.Activity.performCreate(Activity.java:7984)
I MonoDroid:     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
I MonoDroid:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3404)
I MonoDroid:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3595)
I MonoDroid:     at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
I MonoDroid:     at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
I MonoDroid:     at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
I MonoDroid:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
I MonoDroid:     at android.os.Handler.dispatchMessage(Handler.java:106)
I MonoDroid:     at android.os.Looper.loop(Looper.java:223)
I MonoDroid:     at android.app.ActivityThread.main(ActivityThread.java:7660)
I MonoDroid:     at java.lang.reflect.Method.invoke(Native Method)
I MonoDroid:     at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
I MonoDroid:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
I MonoDroid:
W ActivityTaskManager:   Force finishing activity UnnamedProject.UnnamedProject/unnamedproject.unnamedproject.MainActivity

[jonpryor]

@radekdoulik : looks like some tests need updating, e.g. Xamarin.Android.Build.Tests.PackagingTest.CheckIncludedAssemblies

The following Expected files are missing. System.Runtime.Serialization.dll
Expected: False
But was:  True

[dellis1972]

Looks ok as long as its green :)