Revert FPS counter (#17485)

**UPDATE**: Response so far seems to be that this fixes the performance
issues on Intel MacBooks. So we're going to go ahead and merge it.

This reverts the FPS counter added in 11753914d (#16422) because in this
issue someone bisected recent performance regressions down to this
commit:

- https://github.com/zed-industries/zed/issues/16729

Another issue that's possibly related:

-
https://github.com/zed-industries/zed/issues/17305#issuecomment-2332316242

We're reverting this in a PR to create a bundle that people can try out.

Assets:

- Universal Binary:
https://github.com/zed-industries/zed/actions/runs/10735702994/artifacts/1900460781
- x86/Intel:
https://github.com/zed-industries/zed/actions/runs/10735702994/artifacts/1900461236
- Apple Silicon:
https://github.com/zed-industries/zed/actions/runs/10735702994/artifacts/1900460978


Release Notes:

- Removed the recently-added FPS counter since the changes it made to
the Metal renderer on macOS could lead to performance regressions on
Intel MacBooks.

Co-authored-by: Bennet <bennet@zed.dev>

crates/gpui/src/app.rs

@@ -6,7 +6,7 @@ use std::{
     path::{Path, PathBuf},
     rc::{Rc, Weak},
     sync::{atomic::Ordering::SeqCst, Arc},
-    time::{Duration, Instant},
+    time::Duration,
 };
 
 use anyhow::{anyhow, Result};
@@ -142,12 +142,6 @@ impl App {
         self
     }
 
-    /// Sets a start time for tracking time to first window draw.
-    pub fn measure_time_to_first_window_draw(self, start: Instant) -> Self {
-        self.0.borrow_mut().time_to_first_window_draw = Some(TimeToFirstWindowDraw::Pending(start));
-        self
-    }
-
     /// Start the application. The provided callback will be called once the
     /// app is fully launched.
     pub fn run<F>(self, on_finish_launching: F)
@@ -253,7 +247,6 @@ pub struct AppContext {
     pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
     pub(crate) propagate_event: bool,
     pub(crate) prompt_builder: Option<PromptBuilder>,
-    pub(crate) time_to_first_window_draw: Option<TimeToFirstWindowDraw>,
 }
 
 impl AppContext {
@@ -307,7 +300,6 @@ impl AppContext {
                 layout_id_buffer: Default::default(),
                 propagate_event: true,
                 prompt_builder: Some(PromptBuilder::Default),
-                time_to_first_window_draw: None,
             }),
         });
 
@@ -1310,14 +1302,6 @@ impl AppContext {
 
         (task, is_first)
     }
-
-    /// Returns the time to first window draw, if available.
-    pub fn time_to_first_window_draw(&self) -> Option<Duration> {
-        match self.time_to_first_window_draw {
-            Some(TimeToFirstWindowDraw::Done(duration)) => Some(duration),
-            _ => None,
-        }
-    }
 }
 
 impl Context for AppContext {
@@ -1481,15 +1465,6 @@ impl<G: Global> DerefMut for GlobalLease<G> {
     }
 }
 
-/// Represents the initialization duration of the application.
-#[derive(Clone, Copy)]
-pub enum TimeToFirstWindowDraw {
-    /// The application is still initializing, and contains the start time.
-    Pending(Instant),
-    /// The application has finished initializing, and contains the total duration.
-    Done(Duration),
-}
-
 /// Contains state associated with an active drag operation, started by dragging an element
 /// within the window or by dragging into the app from the underlying platform.
 pub struct AnyDrag {