Fix issue where double-tap in ChromeVox doesn't open virtual keyboard.

r701284 (http://crrev.com/c/1825104) made a change that synced to the
selection's deep equivalent in editables. That had the side effect
that when linear-navigating to an editable text field, ChromeVox might
be synced to an element inside the editable text field, rather than
the element itself. That meant ChromeVox didn't trigger its logic to
force a click and open the virtual keyboard when getting a double-tap.

The fix is to ensure that logic runs anywhere inside editable text, not
just on the root editable text element.

See also b/143969599

Bug: 1042902
Change-Id: Ib047ec5b5897653df8266517ac29e00c062c4cbc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2007973
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: David Tseng <dtseng@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733048}

chrome/browser/resources/chromeos/accessibility/chromevox/background/command_handler.js

@@ -553,7 +553,7 @@ CommandHandler.onCommand = function(command) {
         }
 
         if (EventSourceState.get() == EventSourceType.TOUCH_GESTURE &&
-            AutomationPredicate.editText(actionNode)) {
+            actionNode.state.editable) {
           // Dispatch a click to ensure the VK gets shown.
           var location = actionNode.location;
           var event = {