Make wallpaper picker manifest and thumbnails available when offline.

chrome/test/data/extensions/api_test/wallpaper_manager/test.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.
 
 // wallpaperPrivate api test
 // browser_tests --gtest_filter=ExtensionApiTest.wallpaperPrivate
 
 var pass = chrome.test.callbackPass;
 var fail = chrome.test.callbackFail;
 
 chrome.test.getConfig(function(config) {
   var wallpaper;
   var wallpaperStrings;
+  var requestImage = function(url, onLoadCallback) {
+    var wallpaperRequest = new XMLHttpRequest();
+    wallpaperRequest.open('GET', url, true);
+    wallpaperRequest.responseType = 'arraybuffer';
+    try {
+      wallpaperRequest.send(null);
+      wallpaperRequest.onloadend = function(e) {
+        onLoadCallback(wallpaperRequest.status, wallpaperRequest.response);
+      };
+    } catch (e) {
+      console.error(e);
+      chrome.test.fail('An error thrown when requesting wallpaper.');
+    };
+  };
   chrome.test.runTests([
     function getWallpaperStrings() {
       chrome.wallpaperPrivate.getStrings(pass(function(strings) {
         wallpaperStrings = strings;
       }));
     },
     function setOnlineJpegWallpaper() {
-      var wallpaperRequest = new XMLHttpRequest();
       var url = "http://a.com:PORT/files/extensions/api_test" +
           "/wallpaper_manager/test.jpg";
       url = url.replace(/PORT/, config.testServer.port);
-      wallpaperRequest.open('GET', url, true);
-      wallpaperRequest.responseType = 'arraybuffer';
-      try {
-        wallpaperRequest.send(null);
-        wallpaperRequest.onload = function (e) {
-          if (wallpaperRequest.status === 200) {
-              wallpaper = wallpaperRequest.response;
-              chrome.wallpaperPrivate.setWallpaper(wallpaper,
-                                                   'CENTER_CROPPED',
-                                                   url,
-                                                   pass());
-          } else {
-            chrome.test.fail('Failed to load test.jpg from local server.');
-          }
-        };
-      } catch (e) {
-        console.error(e);
-        chrome.test.fail('An error thrown when requesting wallpaper.');
-      };
+      requestImage(url, function(requestStatus, response) {
+        if (requestStatus === 200) {
+          wallpaper = response;
+          chrome.wallpaperPrivate.setWallpaper(wallpaper,
+                                               'CENTER_CROPPED',
+                                               url,
+                                               pass());
+        } else {
+          chrome.test.fail('Failed to load test.jpg from local server.');
+        }
+      });
     },
     function setCustomJpegWallpaper() {
       chrome.wallpaperPrivate.setCustomWallpaper(wallpaper,
                                                  'CENTER_CROPPED',
                                                  pass());
     },
     function setCustomJepgBadWallpaper() {
-      var wallpaperRequest = new XMLHttpRequest();
       var url = "http://a.com:PORT/files/extensions/api_test" +
           "/wallpaper_manager/test_bad.jpg";
       url = url.replace(/PORT/, config.testServer.port);
-      wallpaperRequest.open('GET', url, true);
-      wallpaperRequest.responseType = 'arraybuffer';
-      try {
-        wallpaperRequest.send(null);
-        wallpaperRequest.onload = function (e) {
-          if (wallpaperRequest.status === 200) {
-              var badWallpaper = wallpaperRequest.response;
-              chrome.wallpaperPrivate.setCustomWallpaper(badWallpaper,
-                  'CENTER_CROPPED', fail(wallpaperStrings.invalidWallpaper));
-          } else {
-            chrome.test.fail('Failed to load test_bad.jpg from local server.');
-          }
-        };
-      } catch (e) {
-        console.error(e);
-        chrome.test.fail('An error thrown when requesting wallpaper.');
-      };
+      requestImage(url, function(requestStatus, response) {
+        if (requestStatus === 200) {
+          var badWallpaper = response;
+          chrome.wallpaperPrivate.setCustomWallpaper(badWallpaper,
+              'CENTER_CROPPED', fail(wallpaperStrings.invalidWallpaper));
+        } else {
+          chrome.test.fail('Failed to load test_bad.jpg from local server.');
+        }
+      });
+    },
+    function getAndSetThumbnail() {
+      var url = "http://a.com:PORT/files/extensions/api_test" +
+          "/wallpaper_manager/test.jpg";
+      url = url.replace(/PORT/, config.testServer.port);
+      chrome.wallpaperPrivate.getThumbnail(url, pass(function(data) {
+        chrome.test.assertNoLastError();
+        if (data)
+          chrome.test.fail('Thumbnail is not found. getThumbnail should not ' +
+                           'return any data.');
+        chrome.wallpaperPrivate.saveThumbnail(url, wallpaper, pass(function() {
+          chrome.test.assertNoLastError();
+          chrome.wallpaperPrivate.getThumbnail(url, pass(function(data) {
+            chrome.test.assertNoLastError();
+            // Thumbnail should already be saved to thumbnail directory.
+            chrome.test.assertEq(wallpaper, data);
+          }));
+        }));
+      }));
     }
   ]);
 });