Customize no focus output when using touch

Bug: b/153533629
Change-Id: Ibb16e6fd62768075f30a23c8f4075d6567bb1832
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2157598Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#760738}

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

@@ -321,7 +321,10 @@ CommandHandler.onCommand = function(command) {
   if (!ChromeVoxState.instance.currentRange_) {
     if (!ChromeVoxState.instance.talkBackEnabled) {
       new Output()
-          .withString(Msgs.getMsg('no_focus'))
+          .withString(Msgs.getMsg(
+              EventSourceState.get() == EventSourceType.TOUCH_GESTURE ?
+                  'no_focus_touch' :
+                  'no_focus'))
           .withQueueMode(QueueMode.FLUSH)
           .go();
     }

chrome/browser/resources/chromeos/accessibility/strings/chromevox_strings.grdp

@@ -2915,6 +2915,9 @@
   <message desc="Announced to alert the user that ChromeVox has no current focus." name="IDS_CHROMEVOX_NO_FOCUS">
     No current ChromeVox focus. Press Alt+Shift+L to go to the launcher.
   </message>
+  <message desc="Announced to alert the user that ChromeVox has no current focus when using a touch screen." name="IDS_CHROMEVOX_NO_FOCUS_TOUCH">
+    No current ChromeVox focus. Touch explore to find items.
+  </message>
   <message desc="Labels the checkbox on the options page that enables or disables Smart Sticky Mode. The label explains how the feature works." name="IDS_CHROMEVOX_OPTIONS_SMART_STICKY_MODE">
     Turn off sticky mode when editing text (Smart Sticky Mode)
   </message>