Make wallpaper picker manifest and thumbnails available when offline.

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 0d2ee49213aa1801ac37d25f13aa634e17a4849e..0df65a7cfb5fdc2dd28ca42b87370f644747ae73 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
@@ -32,19 +32,36 @@ cr.define('wallpapers', function() {
     decorate: function() {
       GridItem.prototype.decorate.call(this);
       var imageEl = cr.doc.createElement('img');
-      var xhr = new XMLHttpRequest();
-      xhr.open('GET', this.dataItem.baseURL + ThumbnailSuffix, true);
-      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);
+      chrome.wallpaperPrivate.getThumbnail(this.dataItem.baseURL,
+                                           function(result) {
+        if (result.success) {
+          var data = new Int8Array(result.data);
+          var blob = new Blob([data]);
+          imageEl.src = window.URL.createObjectURL(blob);
           imageEl.addEventListener('load', function(e) {
             window.URL.revokeObjectURL(this.src);
           });
           self.appendChild(imageEl);
+        } else {
+          var xhr = new XMLHttpRequest();
+          xhr.open('GET', self.dataItem.baseURL + ThumbnailSuffix, true);
+          xhr.responseType = 'arraybuffer';
+          xhr.send(null);
+          xhr.addEventListener('load', function(e) {
+            if (xhr.status === 200) {
+              self.textContent = '';
+              chrome.wallpaperPrivate.saveThumbnail(xhr.response,
+                                                    self.dataItem.baseURL);
+              var data = new Int8Array(xhr.response);
+              var blob = new Blob([data]);

[flackr, 2012/11/27 22:04:36]

Combine these two lines, you only use data here.

[bshe, 2012/11/28 18:54:26]

Done.

[flackr, 2012/12/03 19:02:30]

This doesn't look done.

[bshe, 2012/12/03 19:39:32]

Sorry. I changed the one at line 38 but somehow forgot to change here.

Now done for real.

On 2012/12/03 19:02:30, flackr wrote:

+              imageEl.src = window.URL.createObjectURL(blob);
+              imageEl.addEventListener('load', function(e) {
+                window.URL.revokeObjectURL(this.src);
+              });
+              self.appendChild(imageEl);

[flackr, 2012/11/27 22:04:36]

The list of thumbnails grow as we fetch them? We should consider using a
placeholder "loading" image, reserving space so the thumbnails don't shift.

[bshe, 2012/11/28 18:54:26]

The img tag is added to a div. And the div has width/height equal to the
thumbnail image. So the thumbnails shouldn't shift as it loading.

Add a placeholder image sounds great. We just reserve the space currently. Can
we keep it this way right now though? Since I dont have the resource and it may
take a while to get it. Added a todo.

On 2012/11/27 22:04:36, flackr wrote:

[flackr, 2012/12/03 19:02:30]

Yes that sounds good to me.

+            }
+          });
         }
       });
     },