ui2: Reorganize components (#3228)

This PR reorganizes the components in the `ui2` crate.

The distinction between "elements" and "components" is now gone, with
all of the reusable components living under `components/`.

The components that we built while prototyping but will eventually live
in other crates currently reside in the `to_extract/` module.

Release Notes:

- N/A

crates/ui2/src/to_extract/editor_pane.rs

@@ -0,0 +1,77 @@
+use std::path::PathBuf;
+
+use gpui2::{Div, Render, View, VisualContext};
+
+use crate::prelude::*;
+use crate::{
+    hello_world_rust_editor_with_status_example, v_stack, Breadcrumb, Buffer, BufferSearch, Icon,
+    IconButton, IconColor, Symbol, Tab, TabBar, Toolbar,
+};
+
+#[derive(Clone)]
+pub struct EditorPane {
+    tabs: Vec<Tab>,
+    path: PathBuf,
+    symbols: Vec<Symbol>,
+    buffer: Buffer,
+    buffer_search: View<BufferSearch>,
+    is_buffer_search_open: bool,
+}
+
+impl EditorPane {
+    pub fn new(
+        cx: &mut ViewContext<Self>,
+        tabs: Vec<Tab>,
+        path: PathBuf,
+        symbols: Vec<Symbol>,
+        buffer: Buffer,
+    ) -> Self {
+        Self {
+            tabs,
+            path,
+            symbols,
+            buffer,
+            buffer_search: BufferSearch::view(cx),
+            is_buffer_search_open: false,
+        }
+    }
+
+    pub fn toggle_buffer_search(&mut self, cx: &mut ViewContext<Self>) {
+        self.is_buffer_search_open = !self.is_buffer_search_open;
+
+        cx.notify();
+    }
+
+    pub fn view(cx: &mut WindowContext) -> View<Self> {
+        cx.build_view(|cx| hello_world_rust_editor_with_status_example(cx))
+    }
+}
+
+impl Render for EditorPane {
+    type Element = Div<Self>;
+
+    fn render(&mut self, cx: &mut ViewContext<Self>) -> Div<Self> {
+        v_stack()
+            .w_full()
+            .h_full()
+            .flex_1()
+            .child(TabBar::new("editor-pane-tabs", self.tabs.clone()).can_navigate((false, true)))
+            .child(
+                Toolbar::new()
+                    .left_item(Breadcrumb::new(self.path.clone(), self.symbols.clone()))
+                    .right_items(vec![
+                        IconButton::new("toggle_inlay_hints", Icon::InlayHint),
+                        IconButton::<Self>::new("buffer_search", Icon::MagnifyingGlass)
+                            .when(self.is_buffer_search_open, |this| {
+                                this.color(IconColor::Accent)
+                            })
+                            .on_click(|editor, cx| {
+                                editor.toggle_buffer_search(cx);
+                            }),
+                        IconButton::new("inline_assist", Icon::MagicWand),
+                    ]),
+            )
+            .children(Some(self.buffer_search.clone()).filter(|_| self.is_buffer_search_open))
+            .child(self.buffer.clone())
+    }
+}