two nested positioned inlines could paint incorrectly

The parent could have hasText but _not_ have hasForegroundInLayer
due to a layer boundary from one of its children

Author: chearon

src/layout-text.ts

@@ -139,7 +139,7 @@ export class Run extends RenderItem {
         parent.bitfield |= Box.BITS.hasNewlines;
       }
 
-      if (!parent.hasText() && !isSpaceOrTabOrNewline(paragraph[i])) {
+      if (!isSpaceOrTabOrNewline(paragraph[i])) {
         parent.bitfield |= Run.TEXT_BITS;
       }
     }

test/paint.spec.js

@@ -697,6 +697,23 @@ describe('Painting', function () {
     ]);
   });
 
+  it('paints backgrounds below positioned inlines in relative order', function () {
+    this.layout(`
+      Get a
+      <span style="position: relative;">
+        <span style="background-color: #fca; position: relative;">wool</span>
+        blanket
+      </span>
+    `);
+
+    expect(this.paint().getCalls()).to.deep.equal([
+      {t: 'text', x: 0, y: 12.8, text: 'Get a ', fillColor: '#000'},
+      {t: 'text', x: 160, y: 12.8, text: ' blanket', fillColor: '#000'},
+      {t: 'rect', x: 96, y: 0, width: 64, height: 16, fillColor: '#fca'},
+      {t: 'text', x: 96, y: 12.8, text: 'wool', fillColor: '#000'}
+    ]);
+  });
+
   // TODO: would go better in a general box.spec.js
   describe('Pixel snapping', function () {
     it('snaps the border box', function () {