Added 'Next' and 'Previous' links to differential

Summary:
Browsing comments was a bit difficult without the possibllity to jump
between comments. These links will make the browsing easier.

Test Plan:
Tested on multiple diffs that the links were working correctly.

Reviewed By: epriestley
Reviewers: epriestley
CC: jungejason, aran, tuomaspelkonen, epriestley
Differential Revision: 266

src/__celerity_resource_map__.php

@@ -61,6 +61,15 @@ celerity_register_resource_map(array(
     ),
     'disk' => '/rsrc/css/aphront/headsup-action-list-view.css',
   ),
+  'aphront-list-filter-view-css' =>
+  array(
+    'uri' => '/res/e6cff171/rsrc/css/aphront/list-filter-view.css',
+    'type' => 'css',
+    'requires' =>
+    array(
+    ),
+    'disk' => '/rsrc/css/aphront/list-filter-view.css',
+  ),
   0 =>
   array(
     'uri' => '/res/39de799e/rsrc/js/javelin/docs/Base.js',
@@ -71,15 +80,6 @@ celerity_register_resource_map(array(
     ),
     'disk' => '/rsrc/js/javelin/docs/Base.js',
   ),
-  'aphront-list-filter-view-css' =>
-  array(
-    'uri' => '/res/e6cff171/rsrc/css/aphront/list-filter-view.css',
-    'type' => 'css',
-    'requires' =>
-    array(
-    ),
-    'disk' => '/rsrc/css/aphront/list-filter-view.css',
-  ),
   'aphront-pager-view-css' =>
   array(
     'uri' => '/res/43fb79f0/rsrc/css/aphront/pager-view.css',
@@ -322,6 +322,18 @@ celerity_register_resource_map(array(
     ),
     'disk' => '/rsrc/js/application/differential/behavior-add-reviewers.js',
   ),
+  'javelin-behavior-differential-comment-jump' =>
+  array(
+    'uri' => '/res/a84186de/rsrc/js/application/differential/behavior-comment-jump.js',
+    'type' => 'js',
+    'requires' =>
+    array(
+      0 => 'javelin-behavior',
+      1 => 'javelin-util',
+      2 => 'javelin-dom',
+    ),
+    'disk' => '/rsrc/js/application/differential/behavior-comment-jump.js',
+  ),
   'javelin-behavior-differential-diff-radios' =>
   array(
     'uri' => '/res/004cb66f/rsrc/js/application/differential/behavior-diff-radios.js',

src/applications/differential/controller/changesetview/DifferentialChangesetViewController.php

@@ -192,6 +192,8 @@ class DifferentialChangesetViewController extends DifferentialController {
       'whitespace' => $request->getStr('whitespace'),
     ));
 
+    Javelin::initBehavior('differential-comment-jump', array());
+
     $detail = new DifferentialChangesetDetailView();
     $detail->setChangeset($changeset);
     $detail->appendChild($output);
@@ -219,7 +221,8 @@ class DifferentialChangesetViewController extends DifferentialController {
 
     $output =
       '<div class="differential-primary-pane">'.
-        '<div class="differential-review-stage">'.
+        '<div class="differential-review-stage" '.
+          'id="differential-review-stage">'.
           $detail->render().
         '</div>'.
       '</div>';

src/applications/differential/view/changesetlistview/DifferentialChangesetListView.php

@@ -133,6 +133,8 @@ class DifferentialChangesetListView extends AphrontView {
       'uri' => $this->renderURI,
     ));
 
+    Javelin::initBehavior('differential-comment-jump', array());
+
     if ($this->editable) {
       $revision = $this->revision;
       Javelin::initBehavior('differential-edit-inline-comments', array(
@@ -141,7 +143,7 @@ class DifferentialChangesetListView extends AphrontView {
     }
 
     return
-      '<div class="differential-review-stage">'.
+      '<div class="differential-review-stage" id="differential-review-stage">'.
         implode("\n", $output).
       '</div>';
   }

src/applications/differential/view/inlinecomment/DifferentialInlineCommentView.php

@@ -82,6 +82,24 @@ final class DifferentialInlineCommentView extends AphrontView {
 
     $links = array();
 
+    $links[] = javelin_render_tag(
+      'a',
+      array(
+        'href'  => '#',
+        'mustcapture' => true,
+        'sigil' => 'differential-inline-prev',
+      ),
+      'Previous');
+
+    $links[] = javelin_render_tag(
+      'a',
+      array(
+        'href'  => '#',
+        'mustcapture' => true,
+        'sigil' => 'differential-inline-next',
+      ),
+      'Next');
+
     $links[] = javelin_render_tag(
       'a',
       array(

webroot/rsrc/js/application/differential/behavior-comment-jump.js

@@ -0,0 +1,29 @@
+/**
+ * @provides javelin-behavior-differential-comment-jump
+ * @requires javelin-behavior
+ *           javelin-util
+ *           javelin-dom
+ */
+
+JX.behavior('differential-comment-jump', function(config) {
+  function handle_jump(offset) {
+    return (function(e) {
+      var parent = JX.$('differential-review-stage');
+      var clicked = e.getNode('differential-inline-comment');
+      var inlines = JX.DOM.scry(parent, 'div', 'differential-inline-comment');
+      var jumpto = null;
+
+      for (var ii = 0; ii < inlines.length; ii++) {
+        if (inlines[ii] == clicked) {
+          jumpto = inlines[(ii + offset + inlines.length) % inlines.length];
+          break;
+        }
+      }
+      JX.DOM.scrollTo(jumpto);
+      e.kill();
+    });
+  }
+
+  JX.Stratcom.listen('click', 'differential-inline-prev', handle_jump(-1));
+  JX.Stratcom.listen('click', 'differential-inline-next', handle_jump(+1));
+});