Include the overflow of the inline block itself.

Closes #7372.

tests/ref/basic.list

@@ -267,6 +267,7 @@ flaky_cpu == linebreak_simple_a.html linebreak_simple_b.html
 != overconstrained_block.html overconstrained_block_ref.html
 == overflow_auto.html overflow_simple_b.html
 == overflow_auto_stacking_order_a.html overflow_auto_stacking_order_ref.html
+== overflow_position_abs_inline_block.html overflow_position_abs_inline_block_ref.html
 # Should be ==?
 != overflow_position_abs_inside_normal_a.html overflow_position_abs_inside_normal_b.html
 == overflow_position_abs_simple_a.html overflow_position_abs_simple_b.html

tests/ref/overflow_position_abs_inline_block.html

@@ -0,0 +1,23 @@
+<style>
+  #d1 {
+    width: 100px;
+    height: 100px;
+    position: absolute;
+    background: green;
+  }
+  #d2 {
+    display: inline-block;
+    width: 100px;
+    background: red;
+    height: 100px;
+    position: relative;
+    top: 20px;
+    left: 20px;
+  }
+</style>
+
+<div style="position:fixed"></div>
+<div id="d1">
+  <div id="d2"></div>
+</div>
+

tests/ref/overflow_position_abs_inline_block_ref.html

@@ -0,0 +1,23 @@
+<style>
+  #d1 {
+    width: 100px;
+    height: 100px;
+    position: absolute;
+    background: green;
+  }
+  #d2 {
+    display: block;
+    width: 100px;
+    background: red;
+    height: 100px;
+    position: relative;
+    top: 20px;
+    left: 20px;
+  }
+</style>
+
+<div style="position:fixed"></div>
+<div id="d1">
+  <div id="d2"></div>
+</div>
+