part 6: Make `AutoEmptyBlockAncestorDeleter::ScanEmptyBlockInclusiveA…

…ncestor` treat non-editable content as visible

It treats non-editable content as invisible. Therefore, if you try to
delete backward/forward from first/last block, Gecko deletes the block with
the non-editable content.

Depends on D196817

Differential Revision: https://phabricator.services.mozilla.com/D196819

bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1870222
gecko-commit: b9600c5aa59e300200656691d1f1997593caafbd
gecko-reviewers: m_kato

editing/data/delete.js

@@ -3095,4 +3095,10 @@ var browserTests = [
     "<p><span contenteditable=\"false\">abc</span></p>",
     [true],
     {}],
+// Do not delete ancestor blocks which still has non-editable content
+["<p>{}<span contenteditable=false>ab</span></p>",
+    [["delete",""]],
+    "<p><span contenteditable=\"false\">ab</span></p>",
+    [true],
+    {}],
 ]

editing/data/forwarddelete.js

@@ -2975,4 +2975,10 @@ var browserTests = [
     "<p><span contenteditable=\"false\">abc</span></p>",
     [true],
     {}],
+// Do not delete ancestor blocks which still has non-editable content
+["<p><span contenteditable=false>ab</span>{}</p>",
+    [["forwarddelete",""]],
+    "<p><span contenteditable=\"false\">ab</span></p>",
+    [true],
+    {}],
 ]