Auto merge of #12301 - ConnorGBrewster:selection_direction, r=asajeffrey

Take selection direction into account when setting selection

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r? @asajeffrey

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #12300 (github issue number if applicable).

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- [x] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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components/script/textinput.rs

@@ -651,8 +651,17 @@ impl<T: ClipboardProvider> TextInput<T> {
             start = end;
         }
 
-        self.selection_begin = Some(self.get_text_point_for_absolute_point(start));
-        self.edit_point = self.get_text_point_for_absolute_point(end);
+        match self.selection_direction {
+            SelectionDirection::None |
+            SelectionDirection::Forward => {
+                self.selection_begin = Some(self.get_text_point_for_absolute_point(start));
+                self.edit_point = self.get_text_point_for_absolute_point(end);
+            },
+            SelectionDirection::Backward => {
+                self.selection_begin = Some(self.get_text_point_for_absolute_point(end));
+                self.edit_point = self.get_text_point_for_absolute_point(start);
+            }
+        }
         self.assert_ok_selection();
     }