QuickView: Add labels and tabindex for accessibility.

ui/file_manager/file_manager/foreground/elements/files_quick_view.html

Index: ui/file_manager/file_manager/foreground/elements/files_quick_view.html
diff --git a/ui/file_manager/file_manager/foreground/elements/files_quick_view.html b/ui/file_manager/file_manager/foreground/elements/files_quick_view.html
index d0026fd0622dd0e5a63d96abcc764e7b906b553b..69104fcdf2d911991b3d6f83984f18ae14d56864 100644
--- a/ui/file_manager/file_manager/foreground/elements/files_quick_view.html
+++ b/ui/file_manager/file_manager/foreground/elements/files_quick_view.html
@@ -9,6 +9,7 @@
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-dialog/paper-dialog.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-toolbar/paper-toolbar.html">
 <link rel="import" href="files_metadata_box.html">
+<link rel="import" href="files_tooltip.html">
 <link rel="import" href="icons.html">
 
 <dom-module id="files-quick-view">
@@ -18,17 +19,17 @@
       <paper-toolbar id="toolbar">
         <div>[[filePath]]</div>
         <div id="buttons">
-           <paper-button on-tap="onOpenInNewButtonTap" hidden$="[[isUnsupported]]">
+           <paper-button id="open-button" on-tap="onOpenInNewButtonTap" hidden$="[[isUnsupported]]" i18n-values="aria-label:QUICK_VIEW_OPEN_IN_NEW_BUTTON_LABEL" tabindex="0" has-tooltip>
              <iron-icon icon="files:open-in-new"></iron-icon>
            </paper-button>
-           <paper-button toggles active="{{metadataBoxActive}}">
+           <paper-button id-"metadata-button" active="{{metadataBoxActive}}" i18n-values="aria-label:QUICK_VIEW_TOGGLE_METADATA_BOX_BUTTON_LABEL" tabindex="0" toggles has-tooltip>
              <iron-icon  icon="files:info-outline"></iron-icon>
            </paper-button>
         </div>
       </paper-toolbar>
       <div id="mainPanel">
         <div class='close-on-click' id="contentPanel" metadata-box-active$="[[metadataBoxActive]]" on-tap="onContentPanelTap_">
-          <div class='close-on-click' id="innerContentPanel">
+          <div class='close-on-click' id="innerContentPanel" tabindex="0">
             <template is="dom-if" if="[[isImage_(type)]]">
               <div class="close-on-click" generic-thumbnail="image">
                 <img class="content" src="[[contentUrl]]">
@@ -70,6 +71,7 @@
         <files-metadata-box id="metadata-box" hidden$="{{!metadataBoxActive}}"></file-metadata-box>
       </div> <!-- mainPanel -->
     </paper-dialog>
+    <files-tooltip></files-tooltip>
   </template>
 </dom-module>