Remove the remnants of a once-functional visual diff feature

Once upon a time, we could show a diff between what the annotation has
anchored to in the page and the original selected text. That feature has
been non-functional since at least 4f60030.

h/static/scripts/directive/annotation.coffee

@@ -57,8 +57,6 @@ AnnotationController = [
     @preview = 'no'
     @editing = false
     @isSidebar = false
-    @hasDiff = false
-    @showDiff = undefined
     @timestamp = null
 
     model = $scope.annotationGet()
@@ -223,19 +221,6 @@ AnnotationController = [
         this.render()
         this.view()
 
-    # Calculates the visual diff flags from the targets
-    #
-    # hasDiff is set to true is there are any targets with a difference
-    # shouldShowDiff is set to true if there are some meaningful differences
-    #  - that is, more than just uppercase / lowercase
-    diffFromTargets = (targets = []) ->
-      hasDiff = targets.some (t) ->
-        t.diffHTML?
-      shouldShowDiff = hasDiff and targets.some (t) ->
-        t.diffHTML? and not t.diffCaseOnly
-
-      {hasDiff, shouldShowDiff}
-
     # Update the given annotation domain model object with the data from the
     # given annotation view model object.
     updateDomainModel = (domainModel, viewModel) ->
@@ -350,17 +335,6 @@ AnnotationController = [
       # Form the tags for ngTagsInput.
       @annotation.tags = ({text} for text in (model.tags or []))
 
-      # Calculate the visual diff flags
-      diffFlags = diffFromTargets(@annotation.target)
-      @hasDiff = diffFlags.hasDiff
-      if @hasDiff
-        # We don't want to override the showDiff value manually changed
-        # by the user, that's why we use a conditional assignment here,
-        # instead of directly setting showDiff to the calculated value
-        @showDiff ?= diffFlags.shouldShowDiff
-      else
-        @showDiff = undefined
-
     updateTimestamp = (repeat=false) =>
       @timestamp = time.toFuzzyString model.updated
       fuzzyUpdate = time.nextFuzzyUpdate model.updated

h/static/scripts/directive/test/annotation-test.coffee

@@ -340,110 +340,6 @@ describe 'annotation', ->
       controller.render()
       assert(controller.document.title == 'example.com')
 
-    describe 'when there are no targets', ->
-      beforeEach ->
-        annotation.target = []
-        controller.render()
-        targets = controller.annotation.target
-
-      it 'sets `hasDiff` to false and `showDiff` to undefined', ->
-        controller.render()
-        assert.isFalse(controller.hasDiff)
-        assert.isUndefined(controller.showDiff)
-
-    describe 'when a single target has text identical to what was in the selectors', ->
-      it 'sets `showDiff` to undefined and `hasDiff` to false', ->
-        controller.render()
-        assert.isFalse(controller.hasDiff)
-        assert.isUndefined(controller.showDiff)
-
-    describe 'when a single target has different text, compared to what was in the selector', ->
-      targets = null
-
-      beforeEach ->
-        annotation.target = [
-          {diffHTML: "This is <ins>not</ins> the same quote", diffCaseOnly: false},
-        ]
-        controller.render()
-        targets = controller.annotation.target
-
-      it 'sets both `hasDiff` and `showDiff` to true', ->
-        controller.render()
-        assert.isTrue(controller.hasDiff)
-        assert.isTrue(controller.showDiff)
-
-    describe 'when there are only upper case/lower case difference between the text in the single target, and what was saved in a selector', ->
-      targets = null
-
-      beforeEach ->
-        annotation.target = [
-          {diffHTML: "<ins>s</ins><del>S</del>tuff", diffCaseOnly: true},
-        ]
-        controller.render()
-        targets = controller.annotation.target
-
-      it 'sets `hasDiff` to true and `showDiff` to false', ->
-        controller.render()
-        assert.isTrue(controller.hasDiff)
-        assert.isFalse(controller.showDiff)
-
-    describe 'when there are multiple targets, some with differences in text', ->
-      targets = null
-
-      beforeEach ->
-        annotation.target = [
-          {otherProperty: 'bar'},
-          {diffHTML: "This is <ins>not</ins> the same quote", diffCaseOnly: false},
-          {diffHTML: "<ins>s</ins><del>S</del>tuff", diffCaseOnly: true},
-        ]
-        controller.render()
-        targets = controller.annotation.target
-
-      it 'sets `hasDiff` to true', ->
-        assert.isTrue(controller.hasDiff)
-
-      it 'sets `showDiff` to true', ->
-        assert.isTrue(controller.showDiff)
-
-      it 'preserves the `showDiff` value on update', ->
-        controller.showDiff = false
-        annotation.target = annotation.target.slice(1)
-        controller.render()
-        assert.isFalse(controller.showDiff)
-
-      it 'unsets `hasDiff` if differences go away', ->
-        annotation.target = annotation.target.splice(0, 1)
-        controller.render()
-        assert.isFalse(controller.hasDiff)
-
-    describe 'when there are multiple targets, some with differences, but only upper case / lower case', ->
-      targets = null
-
-      beforeEach ->
-        annotation.target = [
-          {otherProperty: 'bar'},
-          {diffHTML: "<ins>s</ins><del>S</del>tuff", diffCaseOnly: true},
-        ]
-        controller.render()
-        targets = controller.annotation.target
-
-      it 'sets `hasDiff` to true', ->
-        assert.isTrue(controller.hasDiff)
-
-      it 'sets `showDiff` to false', ->
-        assert.isFalse(controller.showDiff)
-
-      it 'preserves the `showDiff` value on update', ->
-        controller.showDiff = true
-        annotation.target = annotation.target.slice(1)
-        controller.render()
-        assert.isTrue(controller.showDiff)
-
-      it 'unsets `hasDiff` if differences go away', ->
-        annotation.target = annotation.target.splice(0, 1)
-        controller.render()
-        assert.isFalse(controller.hasDiff)
-
     describe 'timestamp', ->
       clock = null
 

h/static/styles/annotations.scss

@@ -122,11 +122,6 @@
   }
 }
 
-.show-differences {
-  border-left: 3px solid #D3D3D3;
-  padding: 0.3em 0.615em;
-}
-
 
 //PRIVACY CONTROL////////////////////////////
 privacy {

h/templates/client/annotation.html

@@ -58,21 +58,11 @@
            ng-repeat="target in vm.annotation.target track by $index">
     <excerpt enabled="feature('truncate_annotations')">
       <blockquote class="annotation-quote"
-                  ng-hide="target.diffHTML && vm.showDiff"
                   ng-bind-html="selector.exact"
                   ng-repeat="selector in target.selector
                              | filter : {'type': 'TextQuoteSelector'}
                              track by $index"></blockquote>
     </excerpt>
-    <blockquote class="annotation-quote"
-                ng-bind-html="target.diffHTML"
-                ng-show="target.diffHTML && vm.showDiff"></blockquote>
-    <div class="small show-differences"
-         ng-show="vm.hasDiff">
-      <input type="checkbox"
-             ng-model="vm.showDiff"
-             ng-click="$event.stopPropagation()"> Show differences</input>
-    </div>
   </section>
 
   <!-- / Excerpts -- >