Auto merge of #18968 - mbrubeck:try, r=emilio

Use try syntax for Option where appropriate

- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes do not require tests because they are refactoring only

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components/layout/fragment.rs

@@ -2888,10 +2888,7 @@ impl Fragment {
     /// Returns the 4D matrix representing this fragment's transform.
     pub fn transform_matrix(&self, stacking_relative_border_box: &Rect<Au>) -> Option<Transform3D<f32>> {
         let list = &self.style.get_box().transform;
-        let transform = match list.to_transform_3d_matrix(Some(stacking_relative_border_box)) {
-            Some(transform) => transform,
-            None => return None,
-        };
+        let transform = list.to_transform_3d_matrix(Some(stacking_relative_border_box))?;
 
         let transform_origin = &self.style.get_box().transform_origin;
         let transform_origin_x =
@@ -3032,10 +3029,7 @@ impl<'a> Iterator for InlineStyleIterator<'a> {
             self.primary_style_yielded = true;
             return Some(&*self.fragment.style)
         }
-        let inline_context = match self.fragment.inline_context {
-            None => return None,
-            Some(ref inline_context) => inline_context,
-        };
+        let inline_context = self.fragment.inline_context.as_ref()?;
         let inline_style_index = self.inline_style_index;
         if inline_style_index == inline_context.nodes.len() {
             return None

components/layout/inline.rs

@@ -384,10 +384,7 @@ impl LineBreaker {
                                  -> Option<Fragment>
         where I: Iterator<Item=Fragment>,
     {
-        let mut result = match self.next_fragment(old_fragment_iter) {
-            None => return None,
-            Some(fragment) => fragment,
-        };
+        let mut result = self.next_fragment(old_fragment_iter)?;
 
         loop {
             let candidate = match self.next_fragment(old_fragment_iter) {

components/layout/persistent_list.rs

@@ -78,10 +78,7 @@ impl<'a, T> Iterator for PersistentListIterator<'a, T> where T: Send + Sync + 's
 
     #[inline]
     fn next(&mut self) -> Option<&'a T> {
-        let entry = match self.entry {
-            None => return None,
-            Some(entry) => entry,
-        };
+        let entry = self.entry?;
         let value = &entry.value;
         self.entry = match entry.next {
             None => None,