diff --git a/components/layout/construct.rs b/components/layout/construct.rs
index c964501116c..dd6d5ff9930 100644
--- a/components/layout/construct.rs
+++ b/components/layout/construct.rs
@@ -578,7 +578,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                 // Add whitespace results. They will be stripped out later on when
                 // between block elements, and retained when between inline elements.
                 let fragment_info = SpecificFragmentInfo::UnscannedText(
-                    UnscannedTextFragmentInfo::new(" ".to_owned(), None));
+                    box UnscannedTextFragmentInfo::new(" ".to_owned(), None));
                 properties::modify_style_for_replaced_content(&mut whitespace_style);
                 properties::modify_style_for_text(&mut whitespace_style);
                 let fragment = Fragment::from_opaque_node_and_style(whitespace_node,
@@ -715,7 +715,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
 
         match text_content {
             TextContent::Text(string) => {
-                let info = UnscannedTextFragmentInfo::new(string, selection);
+                let info = box UnscannedTextFragmentInfo::new(string, selection);
                 let specific_fragment_info = SpecificFragmentInfo::UnscannedText(info);
                 fragments.fragments.push_back(Fragment::from_opaque_node_and_style(
                         node.opaque(),
@@ -728,7 +728,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                 for content_item in content_items.into_iter() {
                     let specific_fragment_info = match content_item {
                         ContentItem::String(string) => {
-                            let info = UnscannedTextFragmentInfo::new(string, None);
+                            let info = box UnscannedTextFragmentInfo::new(string, None);
                             SpecificFragmentInfo::UnscannedText(info)
                         }
                         content_item => {
@@ -859,7 +859,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                         whitespace_damage)) => {
                     // Instantiate the whitespace fragment.
                     let fragment_info = SpecificFragmentInfo::UnscannedText(
-                        UnscannedTextFragmentInfo::new(" ".to_owned(), None));
+                        box UnscannedTextFragmentInfo::new(" ".to_owned(), None));
                     properties::modify_style_for_replaced_content(&mut whitespace_style);
                     properties::modify_style_for_text(&mut whitespace_style);
                     let fragment = Fragment::from_opaque_node_and_style(whitespace_node,
@@ -1241,7 +1241,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                         unscanned_marker_fragments.push_back(Fragment::new(
                             node,
                             SpecificFragmentInfo::UnscannedText(
-                                UnscannedTextFragmentInfo::new(text, None))));
+                                box UnscannedTextFragmentInfo::new(text, None))));
                         let marker_fragments = TextRunScanner::new().scan_for_runs(
                             &mut self.layout_context.font_context(),
                             unscanned_marker_fragments);
@@ -1848,7 +1848,7 @@ fn control_chars_to_fragment(node: &InlineFragmentNodeInfo,
                              restyle_damage: RestyleDamage)
                              -> Fragment {
     let info = SpecificFragmentInfo::UnscannedText(
-        UnscannedTextFragmentInfo::new(String::from(text), None));
+        box UnscannedTextFragmentInfo::new(String::from(text), None));
     let mut style = node.style.clone();
     properties::modify_style_for_text(&mut style);
     Fragment::from_opaque_node_and_style(node.address,
diff --git a/components/layout/fragment.rs b/components/layout/fragment.rs
index ba7ff2f714e..021efa31a08 100644
--- a/components/layout/fragment.rs
+++ b/components/layout/fragment.rs
@@ -167,7 +167,7 @@ pub enum SpecificFragmentInfo {
     TableWrapper,
     Multicol,
     MulticolColumn,
-    UnscannedText(UnscannedTextFragmentInfo),
+    UnscannedText(Box<UnscannedTextFragmentInfo>),
 }
 
 impl SpecificFragmentInfo {
@@ -896,8 +896,8 @@ impl Fragment {
         let mut unscanned_ellipsis_fragments = LinkedList::new();
         unscanned_ellipsis_fragments.push_back(self.transform(
                 self.border_box.size,
-                SpecificFragmentInfo::UnscannedText(UnscannedTextFragmentInfo::new("…".to_owned(),
-                                                                                   None))));
+                SpecificFragmentInfo::UnscannedText(
+                    box UnscannedTextFragmentInfo::new("…".to_owned(), None))));
         let ellipsis_fragments = TextRunScanner::new().scan_for_runs(&mut layout_context.font_context(),
                                                                      unscanned_ellipsis_fragments);
         debug_assert!(ellipsis_fragments.len() == 1);
diff --git a/components/layout/generated_content.rs b/components/layout/generated_content.rs
index 7af9c4349d2..9cf40b0711f 100644
--- a/components/layout/generated_content.rs
+++ b/components/layout/generated_content.rs
@@ -434,7 +434,8 @@ fn render_text(layout_context: &LayoutContext,
                string: String)
                -> Option<SpecificFragmentInfo> {
     let mut fragments = LinkedList::new();
-    let info = SpecificFragmentInfo::UnscannedText(UnscannedTextFragmentInfo::new(string, None));
+    let info = SpecificFragmentInfo::UnscannedText(
+        box UnscannedTextFragmentInfo::new(string, None));
     fragments.push_back(Fragment::from_opaque_node_and_style(node,
                                                              pseudo,
                                                              style,
diff --git a/components/layout/text.rs b/components/layout/text.rs
index 14b0d138113..049aaabee7e 100644
--- a/components/layout/text.rs
+++ b/components/layout/text.rs
@@ -476,8 +476,8 @@ fn split_first_fragment_at_newline_if_necessary(fragments: &mut LinkedList<Fragm
         }
         first_fragment.transform(first_fragment.border_box.size,
                                  SpecificFragmentInfo::UnscannedText(
-                                     UnscannedTextFragmentInfo::new(string_before,
-                                                                    selection_before)))
+                                     box UnscannedTextFragmentInfo::new(string_before,
+                                                                        selection_before)))
     };
 
     fragments.push_front(new_fragment);
diff --git a/tests/unit/layout/size_of.rs b/tests/unit/layout/size_of.rs
index a404a3f7d81..4c47cee0bd8 100644
--- a/tests/unit/layout/size_of.rs
+++ b/tests/unit/layout/size_of.rs
@@ -7,7 +7,7 @@ use std::mem::size_of;
 
 #[test]
 fn test_size_of_fragment() {
-    let expected = 184;
+    let expected = 160;
     let actual = size_of::<Fragment>();
 
     if actual < expected {