Merge pull request #21807 from RudyLu/keyboard/Bug1038131-remove_sele…

…ctionchange_listener

Bug 1038131 - latin.js failed to deactivate and continue to respond to
r=timdream.

apps/keyboard/js/imes/latin/latin.js

@@ -130,11 +130,11 @@
    */
   var inputSequencePromise = Promise.resolve();
 
-
   // Flag to stop updating suggestions for selectionchange when we're going
   // to do some actions that will cause selectionchange, such as sendKey()
   // or replaceSurroundingText().
   var pendingSelectionChange = 0;
+  var inputContext = null;
 
   // keyboard.js calls this to pass us the interface object we need
   // to communicate with it
@@ -199,7 +199,8 @@
     correcting = (options.correct && inputMode !== 'verbatim');
 
     if (state.inputContext) {
-      state.inputContext.addEventListener('selectionchange', this);
+      inputContext = state.inputContext;
+      inputContext.addEventListener('selectionchange', this);
     }
 
     // Reset our state
@@ -230,6 +231,10 @@
   }
 
   function deactivate() {
+    if (inputContext) {
+      inputContext.removeEventListener('selectionchange', this);
+    }
+
     if (!worker || idleTimer)
       return;
     idleTimer = setTimeout(terminateWorker, workerTimeout);

apps/keyboard/test/unit/latin_test.js

@@ -338,6 +338,7 @@ suite('latin input method capitalization and punctuation', function() {
     var keyboardGlue = Object.create(defaultKeyboardGlue);
     var _windowWorker;
     var workers = [];
+    var handleEventSpy = null;
 
     function activateIME() {
       im.activate('en', {
@@ -365,22 +366,35 @@ suite('latin input method capitalization and punctuation', function() {
       };
 
       worker.prototype.postMessage = function() {};
+
+      handleEventSpy = sinon.spy(im, 'handleEvent');
     });
 
     teardown(function() {
       window.Worker = _windowWorker;
+      handleEventSpy.restore();
     });
 
     test('should listen to selectionchange', function() {
       im.init(keyboardGlue);
       activateIME();
 
-      var handleEventSpy = sinon.spy(im, 'handleEvent');
       inputContext.dispatchEvent(new Event('selectionchange'));
 
       sinon.assert.calledOnce(handleEventSpy);
     });
 
+    test('should stop listening to selectionchange when' +
+         ' deactivated', function() {
+      im.init(keyboardGlue);
+      activateIME();
+
+      im.deactivate();
+
+      inputContext.dispatchEvent(new Event('selectionchange'));
+      sinon.assert.notCalled(handleEventSpy);
+    });
+
     test('wll clear the suggestions if selectionchange', function() {
       im = InputMethods.latin;
       keyboardGlue.sendCandidates = sinon.stub();