[orca] Add support for aria-keyshortcuts

[Joanmarie Diggs <joanied src gnome org>]

commit d69423c87e1f4b00ba83952dd9fd6276af3920fc
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Thu Aug 3 06:32:56 2017 -0400

    Add support for aria-keyshortcuts

 src/orca/scripts/web/script_utilities.py |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)
---
diff --git a/src/orca/scripts/web/script_utilities.py b/src/orca/scripts/web/script_utilities.py
index 803a110..cb01369 100644
--- a/src/orca/scripts/web/script_utilities.py
+++ b/src/orca/scripts/web/script_utilities.py
@@ -1611,6 +1611,19 @@ class Utilities(script_utilities.Utilities):
 
         return roles
 
+    def mnemonicShortcutAccelerator(self, obj):
+        if not (obj and self.inDocumentContent(obj)):
+            return super().mnemonicShortcutAccelerator(obj)
+
+        try:
+            attrs = dict([attr.split(":", 1) for attr in obj.getAttributes()])
+        except:
+            return ["", "", ""]
+
+        keys = map(lambda x: x.replace("+", " "), attrs.get("keyshortcuts", "").split(" "))
+        keys = map(lambda x: x.replace(" ", "+"), map(self.labelFromKeySequence, keys))
+        return ["", " ".join(keys), ""]
+
     def unrelatedLabels(self, root, onlyShowing=True):
         if not (root and self.inDocumentContent(root)):
             return super().unrelatedLabels(root, onlyShowing)