fix(activity-sidebar): render correct copy on only correct moments

Summary:
fixes T3725

changes:
- show the sync mail activity only if number of deltas received is greater than 10
- make the sync mail activity notification persist for longer, since large deltas (>1k) come in intervals of about 25 seconds, which was greater than our previous timeout interval of 15 seconds
- change to clearer copy
- minor style changes to match new copy

Test Plan: tested manually

Reviewers: bengotow

Maniphest Tasks: T3725

Differential Revision: https://phab.nylas.com/D2051

internal_packages/notifications/lib/activity-sidebar-long-poll-store.coffee

@@ -3,6 +3,6 @@ NylasStore = require 'nylas-store'
 
 class AccountSidebarLongPollStore extends NylasStore
   constructor: ->
-    @listenTo Actions.longPollReceivedRawDeltasPing, => @trigger()
+    @listenTo Actions.longPollReceivedRawDeltasPing, (n) => @trigger(n)
 
 module.exports = new AccountSidebarLongPollStore()

internal_packages/notifications/lib/activity-sidebar.cjsx

@@ -94,7 +94,7 @@ class ActivitySidebar extends React.Component
         <div className="progress-track">
           <div className="progress" style={width: "#{progress}%"}></div>
         </div>
-        <div className="inner">Syncing mail data...</div>
+        <div className="inner">Syncing mail data&hellip;</div>
       </div>
 
   _renderTaskActivityItems: =>
@@ -115,11 +115,11 @@ class ActivitySidebar extends React.Component
 
   _renderDeltaSyncActivityItem: =>
     <div className="item" key="delta-sync-item">
-      <div style={padding: "14px 7px 0 10px", float: "left"}>
+      <div style={padding: "8px 7px 0 10px", float: "left"}>
         <RetinaImg name="sending-spinner.gif" mode={RetinaImg.Mode.ContentPreserve} />
       </div>
       <div className="inner">
-        Getting your mail&hellip;this might take a while
+        Syncing mail data&hellip;
       </div>
     </div>
 
@@ -142,14 +142,17 @@ class ActivitySidebar extends React.Component
     tasks: TaskQueueStatusStore.queue()
     sync: NylasSyncStatusStore.state()
 
-  _onDeltaReceived: =>
+  _onDeltaReceived: (countDeltas) =>
+    tooSmallForNotification = countDeltas <= 10
+    return if tooSmallForNotification
+
     if @_timeoutId
       clearTimeout @_timeoutId
 
     @_timeoutId = setTimeout(( =>
       delete @_timeoutId
       @setState receivingDelta: false
-    ), 15000)
+    ), 30000)
 
     @setState receivingDelta: true
 

internal_packages/worker-sync/lib/nylas-sync-worker-pool.coffee

@@ -64,7 +64,7 @@ class NylasSyncWorkerPool
 
   _handleDeltas: (deltas) ->
     Actions.longPollReceivedRawDeltas(deltas)
-    Actions.longPollReceivedRawDeltasPing()
+    Actions.longPollReceivedRawDeltasPing(deltas.length)
 
     # Create a (non-enumerable) reference from the attributes which we carry forward
     # back to their original deltas. This allows us to mark the deltas that the