[toast] Fix <cr-toast> build deps after CL:2144427

CL:2144427 added Polymer iron-a11y-announcer.html to cr_toast.html but
no dep for same to the js_library("cr_toast") build rule: fix that and
add the same dep to js_library("cr_toast.m") per review comments.

Minor: add @private CLosure markup to announceA11yMessage_().

Bug: 1033660, 1002391
Change-Id: Ic0cfbe4177c7813339481dfa5d5c5c7e289f9ad0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2210194
Commit-Queue: dpapad <dpapad@chromium.org>
Reviewed-by: dpapad <dpapad@chromium.org>
Auto-Submit: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#771152}

ui/webui/resources/cr_elements/cr_toast/BUILD.gn

@@ -13,12 +13,12 @@ js_type_check("closure_compile") {
 }
 
 js_library("cr_toast") {
+  deps = [ "//third_party/polymer/v1_0/components-chromium/iron-a11y-announcer:iron-a11y-announcer-extracted" ]
 }
 
 js_library("cr_toast_manager") {
   deps = [
     ":cr_toast",
-    "//third_party/polymer/v1_0/components-chromium/iron-a11y-announcer:iron-a11y-announcer-extracted",
     "//ui/webui/resources/js:assert",
     "//ui/webui/resources/js:cr",
   ]
@@ -60,6 +60,7 @@ js_library("cr_toast.m") {
   sources =
       [ "$root_gen_dir/ui/webui/resources/cr_elements/cr_toast/cr_toast.m.js" ]
   deps = [
+    "//third_party/polymer/v3_0/components-chromium/iron-a11y-announcer:iron-a11y-announcer",
     "//third_party/polymer/v3_0/components-chromium/polymer:polymer_bundled",
   ]
   extra_deps = [ ":cr_toast_module" ]

ui/webui/resources/cr_elements/cr_toast/cr_toast.js

@@ -49,6 +49,7 @@ Polymer({
   /**
    * Announce a11y message
    * @param {string} text
+   * @private
    */
   announceA11yMessage_(text) {
     Polymer.IronA11yAnnouncer.requestAvailability();