Rollup merge of #7015 - mbrubeck:arc-box, r=Ms2ger

Replace Arc<Box<TextRun>> with Arc<TextRun>

Removes an extraneous level of indirection.

r? @pcwalton

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components/layout/fragment.rs

@@ -626,7 +626,7 @@ impl IframeFragmentInfo {
 #[derive(Clone)]
 pub struct ScannedTextFragmentInfo {
     /// The text run that this represents.
-    pub run: Arc<Box<TextRun>>,
+    pub run: Arc<TextRun>,
 
     /// The intrinsic size of the text fragment.
     pub content_size: LogicalSize<Au>,
@@ -646,7 +646,7 @@ pub struct ScannedTextFragmentInfo {
 
 impl ScannedTextFragmentInfo {
     /// Creates the information specific to a scanned text fragment from a range and a text run.
-    pub fn new(run: Arc<Box<TextRun>>,
+    pub fn new(run: Arc<TextRun>,
                range: Range<CharIndex>,
                content_size: LogicalSize<Au>,
                requires_line_break_afterward_if_wrapping_on_newlines: bool)
@@ -689,7 +689,7 @@ pub struct SplitResult {
     /// The part of the fragment that goes on the second line.
     pub inline_end: Option<SplitInfo>,
     /// The text run which is being split.
-    pub text_run: Arc<Box<TextRun>>,
+    pub text_run: Arc<TextRun>,
 }
 
 /// Describes how a fragment should be truncated.
@@ -697,7 +697,7 @@ pub struct TruncationResult {
     /// The part of the fragment remaining after truncation.
     pub split: SplitInfo,
     /// The text run which is being truncated.
-    pub text_run: Arc<Box<TextRun>>,
+    pub text_run: Arc<TextRun>,
 }
 
 /// Data for an unscanned text fragment. Unscanned text fragments are the results of flow
@@ -844,7 +844,7 @@ impl Fragment {
     }
 
     /// Transforms this fragment using the given `SplitInfo`, preserving all the other data.
-    pub fn transform_with_split_info(&self, split: &SplitInfo, text_run: Arc<Box<TextRun>>)
+    pub fn transform_with_split_info(&self, split: &SplitInfo, text_run: Arc<TextRun>)
                                      -> Fragment {
         let size = LogicalSize::new(self.style.writing_mode,
                                     split.inline_size,