windows: Support multi-monitor (#11699)

Zed can detect changes in monitor connections and disconnections and
provide corresponding feedback. For example, if the current window's
display monitor is disconnected, the window will be moved to the primary
monitor. And now Zed always opens on the monitor specified in
`WindowParams`.

Release Notes:

- N/A

crates/gpui/src/platform.rs

@@ -25,10 +25,11 @@ mod test;
 mod windows;
 
 use crate::{
-    Action, AnyWindowHandle, AsyncWindowContext, BackgroundExecutor, Bounds, DevicePixels,
+    point, Action, AnyWindowHandle, AsyncWindowContext, BackgroundExecutor, Bounds, DevicePixels,
     DispatchEventResult, Font, FontId, FontMetrics, FontRun, ForegroundExecutor, GlyphId, Keymap,
     LineLayout, Pixels, PlatformInput, Point, RenderGlyphParams, RenderImageParams,
     RenderSvgParams, Scene, SharedString, Size, Task, TaskLabel, WindowContext,
+    DEFAULT_WINDOW_SIZE,
 };
 use anyhow::Result;
 use async_task::Runnable;
@@ -167,6 +168,14 @@ pub trait PlatformDisplay: Send + Sync + Debug {
 
     /// Get the bounds for this display
     fn bounds(&self) -> Bounds<DevicePixels>;
+
+    /// Get the default bounds for this display to place a window
+    fn default_bounds(&self) -> Bounds<DevicePixels> {
+        let center = self.bounds().center();
+        let offset = DEFAULT_WINDOW_SIZE / 2;
+        let origin = point(center.x - offset.width, center.y - offset.height);
+        Bounds::new(origin, DEFAULT_WINDOW_SIZE)
+    }
 }
 
 /// An opaque identifier for a hardware display