Fix ChromeVox's detection of whether the current document has focus.

chrome/browser/resources/chromeos/chromevox/host/chrome/braille.js

Index: chrome/browser/resources/chromeos/chromevox/host/chrome/braille.js
diff --git a/chrome/browser/resources/chromeos/chromevox/host/chrome/braille.js b/chrome/browser/resources/chromeos/chromevox/host/chrome/braille.js
index 1b202ade3c21134a4de1fd1c2711f856a7643b84..7683ae8adc8410aee78487a0d28bed983dc83f47 100644
--- a/chrome/browser/resources/chromeos/chromevox/host/chrome/braille.js
+++ b/chrome/browser/resources/chromeos/chromevox/host/chrome/braille.js
@@ -49,7 +49,7 @@ cvox.ChromeBraille = function() {
     // within the iframe even though the containing document also has focus.
     // Don't process the event if this document isn't focused or focus lies in
     // a descendant.
-    if (!document.hasFocus() || document.activeElement.tagName == 'IFRAME') {
+    if (!cvox.ChromeVox.documentHasFocus()) {
       return;
     }
     if (msg['message'] == 'BRAILLE' && msg['args']) {