FilesApp: add tooltip to search clear button

Bug: 653007
Change-Id: If42d9ae0a01f5936196a934d6db7bf9603d08213
Reviewed-on: https://chromium-review.googlesource.com/c/1349137Reviewed-by: Stuart Langley <slangley@chromium.org>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610531}

chrome/app/file_manager_strings.grdp

@@ -764,6 +764,9 @@
   <message name="IDS_FILE_BROWSER_SEARCH_TEXT_LABEL" desc="Search text field label.">
     Search
   </message>
+  <message name="IDS_FILE_BROWSER_SEARCH_CLEAR_LABEL" desc="Label to clear search text field">
+    Clear
+  </message>
 
   <message name="IDS_FILE_BROWSER_DEFAULT_NEW_FOLDER_NAME" desc="The default name for a newly created folder.">
     New folder

chrome/app/file_manager_strings_grdp/IDS_FILE_BROWSER_SEARCH_CLEAR_LABEL.png.sha1

+71869860121f1b7760b97b279c96ff8aea684f40
\ No newline at end of file

chrome/browser/chromeos/extensions/file_manager/private_api_strings.cc

@@ -727,6 +727,7 @@ ExtensionFunction::ResponseAction FileManagerPrivateGetStringsFunction::Run() {
   SET_STRING("SEARCH_NO_MATCHING_FILES_HTML",
              IDS_FILE_BROWSER_SEARCH_NO_MATCHING_FILES_HTML);
   SET_STRING("SEARCH_TEXT_LABEL", IDS_FILE_BROWSER_SEARCH_TEXT_LABEL);
+  SET_STRING("SEARCH_CLEAR_LABEL", IDS_FILE_BROWSER_SEARCH_CLEAR_LABEL);
   SET_STRING("SELECT_ALL_COMMAND_LABEL",
              IDS_FILE_BROWSER_SELECT_ALL_COMMAND_LABEL);
   SET_STRING("TASKS_BUTTON_LABEL", IDS_FILE_BROWSER_TASKS_BUTTON_LABEL);

ui/file_manager/file_manager/main.html

@@ -362,7 +362,8 @@
         <div id="search-box">
           <cr-input type="search" tabindex="14" hidden
               i18n-values="aria-label:SEARCH_TEXT_LABEL;placeholder:SEARCH_TEXT_LABEL">
-            <span class="clear" slot="suffix" tabindex="14"></span>
+            <span class="clear" slot="suffix" tabindex="14"
+              i18n-values="aria-label:SEARCH_CLEAR_LABEL" has-tooltip></span>
           </cr-input>
         </div>
         <button id="refresh-button" class="icon-button menu-button" tabindex="15" hidden