Disabling UserImageManagerTest.SaveUserImageFromProfileImage.

This test is timing out relatively consistently. Example:

http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%281%29/builds/50452

BUG=423015
TBR=alemate@chromium.org

Review URL: https://codereview.chromium.org/652773002

Cr-Commit-Position: refs/heads/master@{#299341}

chrome/browser/chromeos/login/users/avatar/user_image_manager_browsertest.cc

@@ -516,7 +516,9 @@ IN_PROC_BROWSER_TEST_F(UserImageManagerTest,
 
 // Verifies that SaveUserImageFromProfileImage() correctly downloads, sets and
 // persists the chosen user image.
-IN_PROC_BROWSER_TEST_F(UserImageManagerTest, SaveUserImageFromProfileImage) {
+// Disabled for timeouts.  https://crbug.com/423015
+IN_PROC_BROWSER_TEST_F(UserImageManagerTest,
+                       DISABLED_SaveUserImageFromProfileImage) {
   const user_manager::User* user =
       user_manager::UserManager::Get()->FindUser(kTestUser1);
   ASSERT_TRUE(user);