Convert wallpaper picker to v2 app

chrome/browser/resources/chromeos/wallpaper_manager/js/wallpaper_images_grid.js

Index: chrome/browser/resources/chromeos/wallpaper_manager/js/wallpaper_images_grid.js
diff --git a/chrome/browser/resources/chromeos/wallpaper_manager/js/wallpaper_images_grid.js b/chrome/browser/resources/chromeos/wallpaper_manager/js/wallpaper_images_grid.js
index cb42b166e915e4dfae5bc026cf1277da84f886e9..91bd38dc8ee4eca5711a8c011e287f4e476bf11d 100644
--- a/chrome/browser/resources/chromeos/wallpaper_manager/js/wallpaper_images_grid.js
+++ b/chrome/browser/resources/chromeos/wallpaper_manager/js/wallpaper_images_grid.js
@@ -32,11 +32,19 @@ cr.define('wallpapers', function() {
     decorate: function() {
       GridItem.prototype.decorate.call(this);
       var imageEl = cr.doc.createElement('img');
-      // Thumbnail
-      imageEl.src = this.dataItem.baseURL + ThumbnailSuffix;
-      // Remove any garbage added by GridItem and ListItem decorators.
-      this.textContent = '';
-      this.appendChild(imageEl);
+      var xhr = new XMLHttpRequest();
+      xhr.open('GET', this.dataItem.baseURL + ThumbnailSuffix, true);

[Mihai Parparita -not on Chrome, 2012/10/12 00:48:47]

What is the base URL in this case? We generally are OK with loading of local
images (they don't have issues when offline).

[bshe, 2012/10/12 16:28:30]

The base URL is a online url.
https://storage.googleapis.com/chromeos-wallpaper-public/timestamp-file-name.png

We want to push new wallpapers to users as soon as possible. If we include them
as local iamges, users will have to wait for chrome update to get the new
wallpapers.

On 2012/10/12 00:48:47, Mihai Parparita wrote:

+      xhr.responseType = 'blob';
+      xhr.send(null);
+      var self = this;
+      xhr.addEventListener('load', function(e) {
+        if (xhr.status === 200) {
+          self.textContent = '';
+          imageEl.src = window.URL.createObjectURL(xhr.response);

[Mihai Parparita -not on Chrome, 2012/10/12 00:48:47]

This will leak the URL, you'll need to call revokeObjectURL once the window is
closing.

[bshe, 2012/10/12 16:28:30]

I saw examples of revoke object after load. After test on my desktop, it seems
work fine. We just need to display the thumbnail and wont do any manipulation on
the URL object after load. So it is probably fine to just revoke them after
load?

On 2012/10/12 00:48:47, Mihai Parparita wrote:

+          self.appendChild(imageEl);
+        }
+        //TODO(bshe): Add error handleing.
+      });
     },
   };