Fix slow resize Embedded Game Window

[Hilderin]

• Fixes Resizing a floating game window is slow #102197

After some testing the performance issue was caused by the NOTIFICATION_PROCESS and NOTIFICATION_RESIZED which triggered a deferred call to EmbeddedProcess::_update_embedded_process each frame which was really unnecessarily. This helps the Floating Window but also the Editor Window when resizing the window or docks.

Using a timer to update the embedded window less frequently seems to work fine. At the same time, I was able to remove the NOTIFICATION_PROCESS from the EmbeddedProcess control which always bothered me.

Note: It does not affect the re-rendering of the game but rather the unresponsiveness of the window.

Note 2: There's an issue actually when resizing the game window, sometime, it stop resizing and focuses the game window. This was fixed in #102247.

[Calinou]

Tested locally on Linux X11 KDE (NVIDIA), it works as expected. It's hard to spot a definitive improvement though.

I assume this will help more on Windows which has historically had more issues with window resize performance.

Forward+

Before

resize_before.mp4

After

resize_after.mp4

Compatibility

Before

resize_before_opengl.mp4

After

resize_after_opengl.mp4

[Hilderin]

I tested on my old computer and the difference is more noticeable. It's far from perfect but it's a bit better.

Godot v4.4.beta (65e14fd) - Windows 10 (build 19045) - Multi-window, 1 monitor - Vulkan (Forward+) - dedicated NVIDIA GeForce 940M (NVIDIA; 30.0.14.7219) - Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz (4 threads)

4.4 beta 2:

dBDacN9PsF.mp4

This PR:

niQwPehAVK.mp4

No embedding:

godot.windows.editor.x86_64_YbdQCGIpfD.mp4

[Hilderin]

I found a bad regression with this PR. When hitting a breakpoint in the script editor, the focus remains on the game window. I'll look into it.
Edit: OK, wow, for this to happen both PR #102251 and #102247 must be merged together!! I pushed a fix in: #102247

[Repiteo]

Thanks!