Remove draft comment from local storage upon discard

Previously, when a user discarded a draft comment, the draft was still
stored in local storage. If they tried to reply to a comment on the same
line, the previous message appeared when it shouldn't have. This change
removes drafts from local storage when they are discarded.

Bug: Issue 4361
Change-Id: Id234676972a21a879e68e754968abf7008098cf6

polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.js

diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.js b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.js
index 8905854..72138ff 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.js
@@ -125,12 +125,7 @@
       this.comment.message = this._messageText;
       this.disabled = true;
 
-      this.$.storage.eraseDraftComment({
-        changeNum: this.changeNum,
-        patchNum: this.patchNum,
-        path: this.comment.path,
-        line: this.comment.line,
-      });
+      this._eraseDraftComment();
 
       this._xhrPromise = this._saveDraft(this.comment).then(function(response) {
         this.disabled = false;
@@ -155,6 +150,15 @@
       }.bind(this));
     },
 
+    _eraseDraftComment: function() {
+      this.$.storage.eraseDraftComment({
+        changeNum: this.changeNum,
+        patchNum: this.patchNum,
+        path: this.comment.path,
+        line: this.comment.line,
+      });
+    },
+
     _commentChanged: function(comment) {
       this.editing = !!comment.__editing;
       if (this.editing) { // It's a new draft/reply, notify.
@@ -338,6 +342,8 @@
       }
       this.editing = false;
       this.disabled = true;
+      this._eraseDraftComment();
+
       if (!this.comment.id) {
         this.disabled = false;
         this._fireDiscard();

polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment_test.html

diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment_test.html b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment_test.html
index 96caebf..f562d3a 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment_test.html
@@ -182,6 +182,7 @@
 
   suite('gr-diff-comment draft tests', function() {
     var element;
+    var sandbox;
 
     setup(function() {
       stub('gr-rest-api-interface', {
@@ -219,6 +220,11 @@
         path: '/path/to/file',
         line: 5,
       };
+      sandbox = sinon.sandbox.create();
+    });
+
+    teardown(function() {
+      sandbox.restore();
     });
 
     test('button visibility states', function() {
@@ -332,6 +338,8 @@
       assert.isTrue(element.editing);
 
       element._messageText = '';
+      var eraseMessageDraftSpy = sandbox.spy(element, '_eraseDraftComment');
+
       // Save should be disabled on an empty message.
       var disabled = element.$$('.save').hasAttribute('disabled');
       assert.isTrue(disabled, 'save button should be disabled.');
@@ -345,18 +353,30 @@
       var numDiscardEvents = 0;
       element.addEventListener('comment-discard', function(e) {
         numDiscardEvents++;
-        if (numDiscardEvents == 3) {
+        assert.isFalse(eraseMessageDraftSpy.called);
+        if (numDiscardEvents === 2) {
           assert.isFalse(updateStub.called);
           done();
         }
       });
       MockInteractions.tap(element.$$('.cancel'));
-      MockInteractions.tap(element.$$('.discard'));
       element.flushDebouncer('fire-update');
       element._messageText = '';
       MockInteractions.pressAndReleaseKeyOn(element.$.editTextarea, 27); // esc
     });
 
+    test('draft discard removes message from storage', function(done) {
+      element._messageText = '';
+      var eraseMessageDraftSpy = sandbox.spy(element, '_eraseDraftComment');
+
+      var numDiscardEvents = 0;
+      element.addEventListener('comment-discard', function(e) {
+        assert.isTrue(eraseMessageDraftSpy.called);
+        done();
+      });
+      MockInteractions.tap(element.$$('.discard'));
+    });
+
     test('ctrl+s saves comment', function(done) {
       var stub = sinon.stub(element, 'save', function() {
         assert.isTrue(stub.called);