[Files app] Add page title and body aria-label

Add page title to have the application name (translated). This fixes
Chromevox reading Files app startup as "WebContents WebContents...",
instead it will read "WebContents Files...".

Add body aria-label. This fixes when the focus is forced to body like
when closing some dialogs Chromevox was reading the whole content of
Files app, which doesn't make sense, now it will read "Files" or its
translated term.

Change-Id: I8566bae97b91b51ea09a2571047bc3790d29f385
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1528125
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#641792}
diff --git a/ui/file_manager/file_manager/main.html b/ui/file_manager/file_manager/main.html
index 2e2780c..76f4cca 100644
--- a/ui/file_manager/file_manager/main.html
+++ b/ui/file_manager/file_manager/main.html
@@ -6,7 +6,7 @@
   -->
 <html dir="$i18n{textdirection}" lang="$i18n{language}">
   <head>
-    <title></title>
+    <title>$i18n{FILEMANAGER_APP_NAME}</title>
 
     <meta name="google" value="notranslate">
     <script src="chrome://resources/polymer/v1_0/html-imports/html-imports.min.js"></script>
@@ -30,7 +30,7 @@
     <script src="foreground/js/main_scripts.js" defer></script>
   </head>
 
-  <body tabindex="-1">
+  <body aria-label="$i18n{FILEMANAGER_APP_NAME}" tabindex="-1">
     <custom-style>
       <style is="custom-style">
         #search-box cr-input {