[orca] Don't treat zero-width no-break space chars as valid offsets

[Joanmarie Diggs <joanied src gnome org>]

commit 84c81570d3947ff3b3c7fa033cc7688915ba01c9
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Thu Apr 18 12:39:18 2019 -0400

    Don't treat zero-width no-break space chars as valid offsets

 src/orca/script_utilities.py             | 1 +
 src/orca/scripts/web/script_utilities.py | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/src/orca/script_utilities.py b/src/orca/script_utilities.py
index 62a925d49..187867647 100644
--- a/src/orca/script_utilities.py
+++ b/src/orca/script_utilities.py
@@ -68,6 +68,7 @@ class Utilities:
     _desktop = pyatspi.Registry.getDesktop(0)
 
     EMBEDDED_OBJECT_CHARACTER = '\ufffc'
+    ZERO_WIDTH_NO_BREAK_SPACE = '\ufeff'
     SUPERSCRIPT_DIGITS = \
         ['\u2070', '\u00b9', '\u00b2', '\u00b3', '\u2074',
          '\u2075', '\u2076', '\u2077', '\u2078', '\u2079']
diff --git a/src/orca/scripts/web/script_utilities.py b/src/orca/scripts/web/script_utilities.py
index 750e4cf2b..85155c1b3 100644
--- a/src/orca/scripts/web/script_utilities.py
+++ b/src/orca/scripts/web/script_utilities.py
@@ -3813,7 +3813,7 @@ class Utilities(script_utilities.Utilities):
                     if child and not self.isZombie(child) and not self.isEmptyAnchor(child) \
                        and not self.isUselessImage(child):
                         return self.findNextCaretInOrder(child, -1)
-                    if allText[i] != self.EMBEDDED_OBJECT_CHARACTER:
+                    if allText[i] not in (self.EMBEDDED_OBJECT_CHARACTER, self.ZERO_WIDTH_NO_BREAK_SPACE):
                         return obj, i
             elif not self.doNotDescendForCaret(obj) and obj.childCount:
                 return self.findNextCaretInOrder(obj[0], -1)
@@ -3879,7 +3879,7 @@ class Utilities(script_utilities.Utilities):
                     if child and not self.isZombie(child) and not self.isEmptyAnchor(child) \
                        and not self.isUselessImage(child):
                         return self.findPreviousCaretInOrder(child, -1)
-                    if allText[i] != self.EMBEDDED_OBJECT_CHARACTER:
+                    if allText[i] not in (self.EMBEDDED_OBJECT_CHARACTER, self.ZERO_WIDTH_NO_BREAK_SPACE):
                         return obj, i
             elif not self.doNotDescendForCaret(obj) and obj.childCount:
                 return self.findPreviousCaretInOrder(obj[obj.childCount - 1], -1)