Bug 1587557: When activating an HTML text field via a11y APIs, if it already has focus, simulate a click. r=MarcoZ

Previously, HTMLTextFieldAccessible::DoAction just called TakeFocus().
When the field already has focus, TakeFocus() will do nothing.
However, the user might be activating this element because they dismissed a touch keyboard and want to bring it back.
Therefore, we must simulate a click so Gecko will bring up the keyboard.

Differential Revision: https://phabricator.services.mozilla.com/D54106

--HG--
extra : moz-landing-system : lando

accessible/html/HTMLFormControlAccessible.cpp

@@ -373,7 +373,14 @@ void HTMLTextFieldAccessible::ActionNameAt(uint8_t aIndex, nsAString& aName) {
 bool HTMLTextFieldAccessible::DoAction(uint8_t aIndex) const {
   if (aIndex != 0) return false;
 
-  TakeFocus();
+  if (FocusMgr()->IsFocused(this)) {
+    // This already has focus, so TakeFocus()will do nothing. However, the user
+    // might be activating this element because they dismissed a touch keyboard
+    // and want to bring it back.
+    DoCommand();
+  } else {
+    TakeFocus();
+  }
   return true;
 }