Add LineWrapper::wrap_shaped_line

This allows us to perform wrapping based on
glyph positions in an already-shaped line. We
plan to use this in the new Text element,
because there we'll already need to do text
shaping as part of layout. This text isn't editable
so it won't need to be rewrapped with the same
frequency as the text editor's content.

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

gpui/src/text_layout.rs

@@ -170,6 +170,10 @@ impl Line {
         Self { layout, color_runs }
     }
 
+    pub fn runs(&self) -> &[Run] {
+        &self.layout.runs
+    }
+
     pub fn width(&self) -> f32 {
         self.layout.width
     }
@@ -245,3 +249,9 @@ impl Line {
         }
     }
 }
+
+impl Run {
+    pub fn glyphs(&self) -> &[Glyph] {
+        &self.glyphs
+    }
+}