Auto merge of #13470 - pcwalton:inline-absolute-hypothetical-baseline, r=notriddle

layout: Improve the interaction between baseline-offset-of-last-line-in-flow logic and inline absolute hypothetical boxes.

See commits for details. These changes place the heart icon on Twitter in the right place.

r? @notriddle

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1 files changed, 8 insertions, 6 deletions

diff --git a/components/layout/inline.rs b/components/layout/inline.rs
index ec1d223cd36..099d9af14d5 100644
--- a/components/layout/inline.rs
+++ b/components/layout/inline.rs
@@ -1262,13 +1262,16 @@ impl InlineFlow {
     }
 
     pub fn baseline_offset_of_last_line(&self) -> Option<Au> {
-        match self.lines.last() {
-            None => None,
-            Some(ref last_line) => {
-                Some(last_line.bounds.start.b + last_line.bounds.size.block -
-                     last_line.inline_metrics.depth_below_baseline)
+        // Find the last line that doesn't consist entirely of hypothetical boxes.
+        for line in self.lines.iter().rev() {
+            if (line.range.begin().get()..line.range.end().get()).any(|index| {
+                !self.fragments.fragments[index as usize].is_hypothetical()
+            }) {
+                return Some(line.bounds.start.b + line.bounds.size.block -
+                            line.inline_metrics.depth_below_baseline)
             }
         }
+        None
     }
 }
 
@@ -1451,7 +1454,6 @@ impl Flow for InlineFlow {
                                            self.minimum_depth_below_baseline);
         scanner.scan_for_lines(self, layout_context);
 
-
         // Now, go through each line and lay out the fragments inside.
         let line_count = self.lines.len();
         for (line_index, line) in self.lines.iter_mut().enumerate() {