Emit decoration events synchronously in legacy spec environment

This is needed to keep a bunch of package tests passing that expect
synchronous decoration updates.

src/display-buffer.coffee

@@ -27,6 +27,7 @@ class DisplayBuffer extends Model
   height: null
   width: null
   didUpdateDecorationsEventScheduled: false
+  updatedSynchronously: false
 
   @deserialize: (state, atomEnvironment) ->
     state.tokenizedBuffer = TokenizedBuffer.deserialize(state.tokenizedBuffer, atomEnvironment)
@@ -186,6 +187,8 @@ class DisplayBuffer extends Model
   # visible - A {Boolean} indicating of the tokenized buffer is shown
   setVisible: (visible) -> @tokenizedBuffer.setVisible(visible)
 
+  setUpdatedSynchronously: (@updatedSynchronously) ->
+
   getVerticalScrollMargin: ->
     maxScrollMargin = Math.floor(((@getHeight() / @getLineHeightInPixels()) - 1) / 2)
     Math.min(@verticalScrollMargin, maxScrollMargin)
@@ -1065,6 +1068,10 @@ class DisplayBuffer extends Model
       @emitter.emit 'did-create-marker', marker
 
   scheduleUpdateDecorationsEvent: ->
+    if @updatedSynchronously
+      @emitter.emit 'did-update-decorations'
+      return
+
     unless @didUpdateDecorationsEventScheduled
       @didUpdateDecorationsEventScheduled = true
       process.nextTick =>

src/text-editor-element.coffee

@@ -103,6 +103,7 @@ class TextEditorElement extends HTMLElement
     return if model.isDestroyed()
 
     @model = model
+    @model.setUpdatedSynchronously(@isUpdatedSynchronously())
     @initializeContent()
     @mountComponent()
     @addGrammarScopeAttribute()
@@ -194,7 +195,9 @@ class TextEditorElement extends HTMLElement
   hasFocus: ->
     this is document.activeElement or @contains(document.activeElement)
 
-  setUpdatedSynchronously: (@updatedSynchronously) -> @updatedSynchronously
+  setUpdatedSynchronously: (@updatedSynchronously) ->
+    @model?.setUpdatedSynchronously(@updatedSynchronously)
+    @updatedSynchronously
 
   isUpdatedSynchronously: -> @updatedSynchronously
 

src/text-editor.coffee

@@ -506,6 +506,9 @@ class TextEditor extends Model
 
   isMini: -> @mini
 
+  setUpdatedSynchronously: (updatedSynchronously) ->
+    @displayBuffer.setUpdatedSynchronously(updatedSynchronously)
+
   onDidChangeMini: (callback) ->
     @emitter.on 'did-change-mini', callback