servo: Merge #17605 - Replace remaining usage of deprecated Range::step_by (from servo:maybereverse); r=nox

… which is being removed in rust-lang/rust#43012

Source-Repo: https://github.com/servo/servo
Source-Revision: 5baea7b73223283b551cf378bb714491a2383c28

UltraBlame original commit: 2828efca932c62b6412d361437ee058577f551ac

Author: marco-c

servo/components/layout/inline.rs

@@ -7982,6 +7982,82 @@ ltr
 )
 }
 ;
+struct
+MaybeReverse
+<
+I
+>
+{
+iter
+:
+I
+reverse
+:
+bool
+}
+impl
+<
+I
+:
+DoubleEndedIterator
+>
+Iterator
+for
+MaybeReverse
+<
+I
+>
+{
+type
+Item
+=
+I
+:
+:
+Item
+;
+fn
+next
+(
+&
+mut
+self
+)
+-
+>
+Option
+<
+I
+:
+:
+Item
+>
+{
+if
+self
+.
+reverse
+{
+self
+.
+iter
+.
+next_back
+(
+)
+}
+else
+{
+self
+.
+iter
+.
+next
+(
+)
+}
+}
+}
 /
 /
 If
@@ -8005,59 +8081,12 @@ reverse
 order
 .
 let
-reverse
-=
-level
-.
-is_ltr
-(
-)
-!
-=
-is_ltr
-;
-let
 fragment_indices
 =
-if
-reverse
+MaybeReverse
 {
-(
-range
-.
-end
-(
-)
-.
-get
-(
-)
--
-1
-.
-.
-range
-.
-begin
-(
-)
-.
-get
-(
-)
--
-1
-)
-.
-step_by
-(
--
-1
-)
-}
-else
-{
-(
+iter
+:
 range
 .
 begin
@@ -8078,12 +8107,16 @@ end
 get
 (
 )
-)
+reverse
+:
+level
 .
-step_by
+is_ltr
 (
-1
 )
+!
+=
+is_ltr
 }
 ;
 for

servo/components/layout/lib.rs

@@ -104,14 +104,6 @@ feature
 raw
 )
 ]
-#
-!
-[
-feature
-(
-step_by
-)
-]
 extern
 crate
 app_units

servo/components/selectors/parser.rs

@@ -12035,15 +12035,6 @@ use
 std
 :
 :
-borrow
-:
-:
-Cow
-;
-use
-std
-:
-:
 collections
 :
 :