[orca] Handle links whose sole content is an image with alt=""

[Joanmarie Diggs <joanied src gnome org>]

commit a61e455ac724eadccca3b0f98ef853661be709b4
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Sat May 23 14:48:44 2020 -0400

    Handle links whose sole content is an image with alt=""
    
    The W3C provides guidance to authors saying that they can use alt=""
    on an image, including in a link, as a way to get screen readers to
    ignore that image. Ideally, this ignoring would be done by the user
    agent -- and is for Chrome/Chromium. But Gecko includes the useless
    image in the accessibility tree, forcing screen readers to do the
    pruning themselves. In addition, when a link whose sole content is
    an image gets focus, Gecko emits a caret-moved event for the offset
    which we're supposed to ignore. As a consequence of this event, Orca
    was looking for the next presentable location. This can be a mistake
    if the next presentable location happens to be another link that the
    user will tab to. Therefore:
    
    * Ignore images with alt="" that are inside links
    * Don't look for the next presentable location when we get a caret-
      moved event for something which we're supposed to pretend doesn't
      exist.

 src/orca/scripts/web/script_utilities.py | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)
---
diff --git a/src/orca/scripts/web/script_utilities.py b/src/orca/scripts/web/script_utilities.py
index 16501f18a..f67e7171b 100644
--- a/src/orca/scripts/web/script_utilities.py
+++ b/src/orca/scripts/web/script_utilities.py
@@ -3766,7 +3766,7 @@ class Utilities(script_utilities.Utilities):
             rv = False
         if rv and obj.getState().contains(pyatspi.STATE_FOCUSABLE):
             rv = False
-        if rv and obj.parent.getRole() == pyatspi.ROLE_LINK:
+        if rv and obj.parent.getRole() == pyatspi.ROLE_LINK and not self.hasExplicitName(obj):
             uri = self.uri(obj.parent)
             if uri and not uri.startswith('javascript'):
                 rv = False
@@ -4792,11 +4792,9 @@ class Utilities(script_utilities.Utilities):
             return obj, offset + 1
 
         if not self._canHaveCaretContext(child):
-            nextObj, nextOffset = self.nextContext(obj, offset)
-            msg = "WEB: First caret context for %s, %i is %s, %i (child cannot be context)" % \
-                (obj, offset, nextObj, nextOffset)
+            msg = "WEB: Child cannot be context. Returning %s, %i unchanged." % (obj, offset)
             debug.println(debug.LEVEL_INFO, msg, True)
-            return nextObj, nextOffset
+            return obj, offset
 
         msg = "WEB: Looking in child %s for first caret context for %s, %i" % (child, obj, offset)
         debug.println(debug.LEVEL_INFO, msg, True)