Invalidate each chip if it loads avatar on background

The chip might not redraw itself when it loads the avatar
asynchronously (works for Gmail, but it seems to not work
on some other projects that use chips). Let's just force
redraw the individual chip's view upon loading.

Change-Id: I3647591fc4c09ad895a58ed67b02fa71bddbe173
diff --git a/src/com/android/ex/chips/RecipientEditTextView.java b/src/com/android/ex/chips/RecipientEditTextView.java
index 7a8dc8e..af263a0 100644
--- a/src/com/android/ex/chips/RecipientEditTextView.java
+++ b/src/com/android/ex/chips/RecipientEditTextView.java
@@ -769,6 +769,8 @@
                             }
                             // This is called on the main thread so we can draw the icon here
                             drawIcon(bitmapContainer, icon, paint);
+                            // The view might not redraw itself since it's loaded in the background
+                            invalidate();
                         }
                 });
             } else {