Examples: Win32: Let the CPU and GPU chill when minimized

[CovERUshKA]

When the window is minimized, in the task manager i see 100% GPU usage and 10% CPU usage
When the window is restored, i see 7% GPU usage and 0,5% CPU usage

So i added SIZE_MINIMIZED handling, to prevent CPU and GPU usage when the window is minimized

[kayws426]

I have tested with your code-changes, but I found another problem.

Reproduce the problem (my machine runs Window 10 Pro 19042.867):

1. Maximize the window.
2. Minimize the window. (You can see low-usage for GPU and CPU. This is good, but...)
3. Restore the window. (The Problem: Window content does not update.)

Caused by:

• g_wndMinimized still have true value even though window have restored(maximized).
• The Window receives a WM_SIZE event with wParam = SIZE_MAXIMIZED, not SIZE_RESTORED in this case.

Maybe a simple solution is:

-        if (wParam == SIZE_MINIMIZED)
-        {
-            g_wndMinimized = true;
-        }
-        else if (wParam == SIZE_RESTORED)
-        {
-            g_wndMinimized = false;
-        }
+        g_wndMinimized = (wParam == SIZE_MINIMIZED);

[ocornut]

Thank you for the PR and sorry for my late reaction.
As mentioned in #7615, I think this PR would indeed fix things for minimization, but not fix the issue for screen locking.

I have pushed ec1d2be which seemingly solves it for both cases. Implemented this for the DX9, DX10, DX11 and DX12 examples. Both DX9 and DX12 weren't burning as much CPU when looping with no visible swap chain, as Present() would still honor vsync, but it's still best to not loop when locked.

Note this issue for multi-viewports #7615 (comment)