feat(shortcuts): Pageup/dn in message list, shift+pageup/dn in thread list

internal_packages/message-list/lib/message-list.cjsx

@@ -77,6 +77,8 @@ class MessageList extends React.Component
       'application:reply': => @_createReplyOrUpdateExistingDraft('reply')
       'application:reply-all': => @_createReplyOrUpdateExistingDraft('reply-all')
       'application:forward': => @_onForward()
+      'core:messages-page-up': => @_onScrollByPage(-1)
+      'core:messages-page-down': => @_onScrollByPage(1)
 
     @command_unsubscriber = atom.commands.add('body', commands)
 
@@ -366,6 +368,10 @@ class MessageList extends React.Component
     else
       throw new Error("onChildScrollRequest: expected clientId or rect")
 
+  _onScrollByPage: (direction) =>
+    height = React.findDOMNode(@refs.messageWrap).clientHeight
+    @refs.messageWrap.scrollTop += height * direction
+
   _onChange: =>
     newState = @_getStateFromStores()
     if @state.currentThread isnt newState.currentThread

keymaps/base.cson

@@ -10,9 +10,14 @@
   'up'       : 'core:previous-item'
   'down'     : 'core:next-item'
   'enter'    : 'core:focus-item'
-  'delete': 'core:remove-from-view'
+  'delete'   : 'core:remove-from-view'
   'backspace': 'core:remove-from-view'
 
+  'pageup'   : 'core:messages-page-up'
+  'pagedown' : 'core:messages-page-down'
+  'shift-pageup'   : 'core:list-page-up'
+  'shift-pagedown' : 'core:list-page-down'
+
   # Default cross-platform core behaviors
   'left': 'core:move-left'
   'right': 'core:move-right'
@@ -20,8 +25,6 @@
   'shift-down': 'core:select-down'
   'shift-left': 'core:select-left'
   'shift-right': 'core:select-right'
-  'shift-pageup': 'core:select-page-up'
-  'shift-pagedown': 'core:select-page-down'
   'shift-delete': 'core:cut'
 
 # Inputs are native by default.

src/components/list-tabular.cjsx

@@ -173,6 +173,10 @@ class ListTabular extends React.Component
   scrollTo: (node) =>
     @refs.container.scrollTo(node)
 
+  scrollByPage: (direction) =>
+    height = React.findDOMNode(@refs.container).clientHeight
+    @refs.container.scrollTop += height * direction
+
 
 ListTabular.Item = ListTabularItem
 ListTabular.Column = ListColumn

src/components/multiselect-list.cjsx

@@ -76,6 +76,8 @@ class MultiselectList extends React.Component
       'core:previous-item': => @_onShift(-1)
       'core:select-down': => @_onShift(1, {select: true})
       'core:select-up': => @_onShift(-1, {select: true})
+      'core:list-page-up': => @_onScrollByPage(-1)
+      'core:list-page-down': => @_onScrollByPage(1)
       'application:pop-sheet': => @_onDeselect()
 
     Object.keys(props.commands).forEach (key) =>
@@ -163,6 +165,9 @@ class MultiselectList extends React.Component
     return unless @state.handler
     @state.handler.onShift(delta, options)
 
+  _onScrollByPage: (delta) =>
+    @refs.list.scrollByPage(delta)
+
   _onChange: =>
     @setState(@_getStateFromStores())