Replace the index mapping of wallpaper picker UI and hard coded wallpaper index in C++

chrome/browser/resources/options2/chromeos/set_wallpaper_options.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 cr.define('options', function() {
 
   var OptionsPage = options.OptionsPage;
   var UserImagesGrid = options.UserImagesGrid;
 
   /////////////////////////////////////////////////////////////////////////////
@@ skipping 59 matching lines @@
 
     /**
      * Called right before the page is hidden.
      */
     willHidePage: function() {
       var wallpaperGrid = $('wallpaper-grid');
       wallpaperGrid.blur();
     },
 
     /**
+     * Set attributions of wallpaper with given URL.
+     * @param {string} url URL of the selected wallpaper.
+     * @private
+     */
+    setWallpaperAttribution_: function(url) {
+      for (var i = 0; i < this.wallpapers_.length; i++) {
+        if (this.wallpapers_[i].url == url) {
+          $('author-name').textContent = this.wallpapers_[i].author;
+          $('author-website').textContent = this.wallpapers_[i].website;
+          return;
+        }
+      }
+      $('author-name').textContent = '';
+      $('author-website').textContent = '';
+    },
+
+    /**
      * Handles image selection change.
      * @private
      */
     handleImageSelected_: function() {
       var wallpaperGrid = $('wallpaper-grid');
-      var index = wallpaperGrid.selectionModel.selectedIndex;
-      $('author-name').innerText = this.wallpapers_[index].author;
-      $('author-website').innerText = this.wallpapers_[index].website;
-
-      // Ignore deselection, selection change caused by program itself and
-      // selection of one of the action buttons.
-      if (index != -1 &&
+      var url = wallpaperGrid.selectedItemUrl;
+      if (url &&
           !wallpaperGrid.inProgramSelection) {
-        chrome.send('selectWallpaper', [index.toString()]);
+        this.setWallpaperAttribution_(url);
+        chrome.send('selectWallpaper', [url]);
       }
     },
 
     /**
      * Handles double click on the image grid.
      * @param {Event} e Double click Event.
      */
     handleImageDblClick_: function(e) {
       // Close page unless the click target is the grid itself.
       if (e.target instanceof HTMLImageElement)
         OptionsPage.closeOverlay();
     },
 
     /**
-     * Selects user image with the given index.
-     * @param {int} index index of the image to select.
+     * Selects corresponding wallpaper thumbnail with the given URL.
+     * @param {string} url URL of the wallpaper thumbnail to select.
      * @private
      */
-    setSelectedImage_: function(index) {
-      var wallpaperGrid = $('wallpaper-grid');
-      wallpaperGrid.selectedItemIndex = index;
-      $('author-name').innerText = this.wallpapers_[index].author;
-      $('author-website').innerText = this.wallpapers_[index].website;
+    setSelectedImage_: function(url) {
+      $('wallpaper-grid').selectedItemUrl = url;
+      this.setWallpaperAttribution_(url);
     },
 
     /**
      * Appends default images to the image grid. Should only be called once.
      * @param {Array.<{author: string, url: string, website: string}>}
      * wallpapers An array of wallpaper objects.
      * @private
      */
     setDefaultImages_: function(wallpapers) {
       var wallpaperGrid = $('wallpaper-grid');
@@ skipping 20 matching lines @@
     };
   });
 
   // Export
   return {
     SetWallpaperOptions: SetWallpaperOptions
   };
 
 });