[android] call PlatformContentViewGroup.postInvalidate() less

[jonathanpeppers]

Context: #23991

@chabiss's sample app is running a lot of GCs:

[riodictablemaui] Explicit concurrent copying GC freed 933(127KB) AllocSpace objects, 31(4092KB) LOS objects, 49% free, 4423KB/8846KB, paused 1.328ms,169us total 33.513ms
[riodictablemaui] Explicit concurrent copying GC freed 722(46KB) AllocSpace objects, 0(0B) LOS objects, 49% free, 4581KB/9162KB, paused 1.856ms,170us total 14.835ms
[riodictablemaui] Explicit concurrent copying GC freed 641(43KB) AllocSpace objects, 1(108KB) LOS objects, 49% free, 4525KB/9050KB, paused 1.420ms,176us total 14.112ms
[riodictablemaui] Explicit concurrent copying GC freed 619(41KB) AllocSpace objects, 0(0B) LOS objects, 49% free, 4579KB/9158KB, paused 1.263ms,173us total 13.825ms
... many many more lines

This doesn't seem like a normal amount of GCs for a simple app like this.

Attaching Android Studio's allocation profiler, I can see a significant amount of allocations at:

com.microsoft.maui.PlatformContentViewGroup.setHasClip()
    Allocations: 35,906
    Deallocations: 143
    Total Count: 35,763
    Shallow Size: 2,288,832

The call to postInvalidate() is running a lot, and this causes:

• A layout cycle

• android.os.Message to be allocated

• etc. etc.

I think we can simply check if hasClip has changed, and only call postInvalidate() if it has.

[jonathanpeppers]

I was testing this change with a Stopwatch:

public async Task RefreshView()
{
    if (this.IsRefreshing)
    {
        return;
    }

    Console.WriteLine($"RefreshView starting");
    var sw = new System.Diagnostics.Stopwatch();
    sw.Start();
    this.IsRefreshing = true;
    PeriodicTableDataModel dataModel = await this.GetDataModelAsync();
    if(dataModel != null)
    {
        var observable = new ObservableCollection<ElementViewModel>();
        foreach(var element in dataModel.Elements) 
        {
            observable.Add(new ElementViewModel(element));
        }
        this.Elements = observable;
        OnPropertyChanged(nameof(Elements));
    }
    this.IsRefreshing = false;

    sw.Stop();
    Console.WriteLine($"RefreshView took {sw.ElapsedMilliseconds} ms");
}

Before it was around 17 seconds debugging on a Pixel 7, with this change it's:

[DOTNET] RefreshView took 8569 ms

Using dotnet/maui/main, I see some log messages like this, so there might be other things we can improve:

[0:] Microsoft.Maui.Controls.Xaml.Diagnostics.BindingDiagnostics: Warning: Mismatch between the specified x:DataType and the current binding context

[jonathanpeppers]

/azp run

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