In some cases, the reply dialog could be opened before all comment
drafts have been saved, causing the draft to not appear in the dialog.
This change maintains an array corresponding to each draft request and
refers to it before opening the reply dialog. If the array is populated,
a non-blocking alert is shown with the text 'Try again when all comments
have saved.'
Bug: Issue 5369
Change-Id: Ieb73e7d7b4f66daff6cc2278a84c2195b7d0e541
6cff0e60d6