Bug 937291: Limit overflow of each group list.
Bug 937240 - [COST CONTROL] Remove the  module mindgap and filtering operations of historical data
Merge pull request #13948 from gitmai/bug-937240-remove-mindgap

Bug 937240 - [COST CONTROL] Remove the  module mindgap and filtering ope...
r=salva
Merge pull request #13925 from wanderview/contacts-group-overflow-3

Bug 937291: Limit overflow of each group list.  r=arcturus
Bug 935177 - [Messages][Drafts] Remove "discard message" confirmation prompt