Adds a small icon to notifications, and connects it to synced notifications.

ui/message_center/message_center_impl_unittest.cc

Index: ui/message_center/message_center_impl_unittest.cc
diff --git a/ui/message_center/message_center_impl_unittest.cc b/ui/message_center/message_center_impl_unittest.cc
index 1e8ab41f29cd395d8adaffbd6927cd60dd5e5d79..b223ad92d4a1be3678fde99c0b25454e478a28dd 100644
--- a/ui/message_center/message_center_impl_unittest.cc
+++ b/ui/message_center/message_center_impl_unittest.cc
@@ -706,6 +706,7 @@ TEST_F(MessageCenterImplTest, QueuedDirectUpdates) {
   gfx::Image testImage(gfx::Image(gfx::ImageSkia(canvas.ExtractImageRep())));
   message_center()->SetNotificationIcon(id, testImage);
   message_center()->SetNotificationImage(id, testImage);
+  message_center()->SetNotificationSmallImage(id, testImage);
   message_center()->SetNotificationButtonIcon(id, 0, testImage);
   message_center()->SetNotificationButtonIcon(id, 1, testImage);
 
@@ -724,6 +725,7 @@ TEST_F(MessageCenterImplTest, QueuedDirectUpdates) {
 
   EXPECT_EQ(new_size, mc_notification->icon().Size());
   EXPECT_EQ(new_size, mc_notification->image().Size());
+  EXPECT_EQ(new_size, mc_notification->small_image().Size());
   EXPECT_EQ(new_size, buttons[0].icon.Size());
   EXPECT_EQ(new_size, buttons[1].icon.Size());
 }