Propagate a did-use-grammar event out of the tokenized buffer.

src/display-buffer.coffee

@@ -137,6 +137,9 @@ class DisplayBuffer extends Model
   onDidChangeGrammar: (callback) ->
     @tokenizedBuffer.onDidChangeGrammar(callback)
 
+  onDidUseGrammar: (callback) ->
+    @tokenizedBuffer.onDidUseGrammar(callback)
+
   onDidTokenize: (callback) ->
     @tokenizedBuffer.onDidTokenize(callback)
 

src/text-editor.coffee

@@ -325,6 +325,9 @@ class TextEditor extends Model
   onDidChangeGrammar: (callback) ->
     @emitter.on 'did-change-grammar', callback
 
+  onDidUseGrammar: (callback) ->
+    @displayBuffer.onDidUseGrammar(callback)
+
   # Extended: Calls your `callback` when the result of {::isModified} changes.
   #
   # * `callback` {Function}

src/tokenized-buffer.coffee

@@ -126,9 +126,12 @@ class TokenizedBuffer extends Model
     @disposables.add(@configSubscriptions)
 
     @retokenizeLines()
-    @packageManager.triggerActivationHook("#{grammar.packageName}:grammar-used")
+    @emitter.emit 'did-use-grammar', grammar
     @emitter.emit 'did-change-grammar', grammar
 
+  onDidUseGrammar: (callback) ->
+    @emitter.on 'did-use-grammar', callback
+
   getGrammarSelectionContent: ->
     @buffer.getTextInRange([[0, 0], [10, 0]])