Fix issues where screen and window sizes contained Pixels, but were declared as DevicePixels (#12991)

On most platforms, things were working correctly, but had the wrong
type. On X11, there were some problems with window and display size
calculations.

Release Notes:

- Fixed issues with window positioning on X11

---------

Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>
Co-authored-by: Mikayla <mikayla@zed.dev>

crates/gpui/src/platform/test/display.rs

@@ -1,12 +1,11 @@
+use crate::{px, Bounds, DisplayId, Pixels, PlatformDisplay, Point};
 use anyhow::{Ok, Result};
 
-use crate::{Bounds, DevicePixels, DisplayId, PlatformDisplay, Point};
-
 #[derive(Debug)]
 pub(crate) struct TestDisplay {
     id: DisplayId,
     uuid: uuid::Uuid,
-    bounds: Bounds<DevicePixels>,
+    bounds: Bounds<Pixels>,
 }
 
 impl TestDisplay {
@@ -14,10 +13,7 @@ impl TestDisplay {
         TestDisplay {
             id: DisplayId(1),
             uuid: uuid::Uuid::new_v4(),
-            bounds: Bounds::from_corners(
-                Point::default(),
-                Point::new(DevicePixels(1920), DevicePixels(1080)),
-            ),
+            bounds: Bounds::from_corners(Point::default(), Point::new(px(1920.), px(1080.))),
         }
     }
 }
@@ -31,7 +27,7 @@ impl PlatformDisplay for TestDisplay {
         Ok(self.uuid)
     }
 
-    fn bounds(&self) -> crate::Bounds<crate::DevicePixels> {
+    fn bounds(&self) -> crate::Bounds<crate::Pixels> {
         self.bounds
     }
 }

crates/gpui/src/platform/test/window.rs

@@ -1,8 +1,8 @@
 use crate::{
-    AnyWindowHandle, AtlasKey, AtlasTextureId, AtlasTile, Bounds, DevicePixels,
-    DispatchEventResult, Pixels, PlatformAtlas, PlatformDisplay, PlatformInput,
-    PlatformInputHandler, PlatformWindow, Point, Size, TestPlatform, TileId, WindowAppearance,
-    WindowBackgroundAppearance, WindowBounds, WindowParams,
+    AnyWindowHandle, AtlasKey, AtlasTextureId, AtlasTile, Bounds, DispatchEventResult, Pixels,
+    PlatformAtlas, PlatformDisplay, PlatformInput, PlatformInputHandler, PlatformWindow, Point,
+    Size, TestPlatform, TileId, WindowAppearance, WindowBackgroundAppearance, WindowBounds,
+    WindowParams,
 };
 use collections::HashMap;
 use parking_lot::Mutex;
@@ -13,7 +13,7 @@ use std::{
 };
 
 pub(crate) struct TestWindowState {
-    pub(crate) bounds: Bounds<DevicePixels>,
+    pub(crate) bounds: Bounds<Pixels>,
     pub(crate) handle: AnyWindowHandle,
     display: Rc<dyn PlatformDisplay>,
     pub(crate) title: Option<String>,
@@ -79,7 +79,7 @@ impl TestWindow {
         let Some(mut callback) = lock.resize_callback.take() else {
             return;
         };
-        lock.bounds.size = size.map(|pixels| (pixels.0 as i32).into());
+        lock.bounds.size = size;
         drop(lock);
         callback(size, scale_factor);
         self.0.lock().resize_callback = Some(callback);
@@ -108,7 +108,7 @@ impl TestWindow {
 }
 
 impl PlatformWindow for TestWindow {
-    fn bounds(&self) -> Bounds<DevicePixels> {
+    fn bounds(&self) -> Bounds<Pixels> {
         self.0.lock().bounds
     }
 
@@ -121,7 +121,7 @@ impl PlatformWindow for TestWindow {
     }
 
     fn content_size(&self) -> Size<Pixels> {
-        self.bounds().size.into()
+        self.bounds().size
     }
 
     fn scale_factor(&self) -> f32 {