Merge branch '21369-make-it-clearer-that-diffs-can-be-collapsed' into 'master'

Updated diff toggle targets and added icon

## What does this MR do?

Adds the new diff toggle icon and alters the toggle targets.

User can now click on the file header bar _(where no other elements are above it, apart from the icon)_ and the `Click to expand` link to expand the diff and no where else.

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

## Screenshots (if relevant)

![Screen_Shot_2016-09-02_at_15.35.15](/uploads/c1cb8c0547328153250294d6c95dd96a/Screen_Shot_2016-09-02_at_15.35.15.png)

####  Gif

![2016-09-02_15.34.31](/uploads/abaefaeba9ce8ef129522dae34574c57/2016-09-02_15.34.31.gif)

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Closes #21369 

Closes #20326

See merge request !6183

5 files changed, 25 insertions, 8 deletions

diff --git a/app/assets/javascripts/single_file_diff.js b/app/assets/javascripts/single_file_diff.js
index 156b9b8abec..ee6af123268 100644
--- a/app/assets/javascripts/single_file_diff.js
+++ b/app/assets/javascripts/single_file_diff.js
@@ -10,12 +10,13 @@
 
     ERROR_HTML = '<div class="nothing-here-block"><i class="fa fa-warning"></i> Could not load diff</div>';
 
-    COLLAPSED_HTML = '<div class="nothing-here-block diff-collapsed">This diff is collapsed. Click to expand it.</div>';
+    COLLAPSED_HTML = '<div class="nothing-here-block diff-collapsed">This diff is collapsed. <a class="click-to-expand">Click to expand it.</a></div>';
 
     function SingleFileDiff(file) {
       this.file = file;
       this.toggleDiff = bind(this.toggleDiff, this);
       this.content = $('.diff-content', this.file);
+      this.$toggleIcon = $('.diff-toggle-caret', this.file);
       this.diffForPath = this.content.find('[data-diff-for-path]').data('diff-for-path');
       this.isOpen = !this.diffForPath;
       if (this.diffForPath) {
@@ -23,18 +24,22 @@
         this.loadingContent = $(WRAPPER).addClass('loading').html(LOADING_HTML).hide();
         this.content = null;
         this.collapsedContent.after(this.loadingContent);
+        this.$toggleIcon.addClass('fa-caret-right');
       } else {
         this.collapsedContent = $(WRAPPER).html(COLLAPSED_HTML).hide();
         this.content.after(this.collapsedContent);
+        this.$toggleIcon.addClass('fa-caret-down');
       }
-      this.collapsedContent.on('click', this.toggleDiff);
-      $('.file-title > a', this.file).on('click', this.toggleDiff);
+      $('.file-title, .click-to-expand', this.file).on('click', this.toggleDiff);
     }
 
     SingleFileDiff.prototype.toggleDiff = function(e) {
+      var $target = $(e.target);
+      if (!$target.hasClass('file-title') && !$target.hasClass('click-to-expand') && !$target.hasClass('diff-toggle-caret')) return;
       this.isOpen = !this.isOpen;
       if (!this.isOpen && !this.hasError) {
         this.content.hide();
+        this.$toggleIcon.addClass('fa-caret-right').removeClass('fa-caret-down');
         this.collapsedContent.show();
         if (typeof DiffNotesApp !== 'undefined') {
           DiffNotesApp.compileComponents();
@@ -42,10 +47,12 @@
       } else if (this.content) {
         this.collapsedContent.hide();
         this.content.show();
+        this.$toggleIcon.addClass('fa-caret-down').removeClass('fa-caret-right');
         if (typeof DiffNotesApp !== 'undefined') {
           DiffNotesApp.compileComponents();
         }
       } else {
+        this.$toggleIcon.addClass('fa-caret-down').removeClass('fa-caret-right');
         return this.getContentHTML();
       }
     };
diff --git a/app/assets/stylesheets/framework/blocks.scss b/app/assets/stylesheets/framework/blocks.scss
index 2432ddb72f4..d315db4cb32 100644
--- a/app/assets/stylesheets/framework/blocks.scss
+++ b/app/assets/stylesheets/framework/blocks.scss
@@ -19,10 +19,8 @@
 
   &.diff-collapsed {
     padding: 5px;
-    cursor: pointer;
-
-    &:hover {
-      background-color: $row-hover;
+    .click-to-expand {
+      cursor: pointer;
     }
   }
 }
diff --git a/app/assets/stylesheets/framework/files.scss b/app/assets/stylesheets/framework/files.scss
index 76a3c083697..81520500594 100644
--- a/app/assets/stylesheets/framework/files.scss
+++ b/app/assets/stylesheets/framework/files.scss
@@ -26,6 +26,15 @@
     padding: 10px $gl-padding;
     word-wrap: break-word;
     border-radius: 3px 3px 0 0;
+    cursor: pointer;
+
+    &:hover {
+      background-color: $dark-background-color;
+    }
+
+    .diff-toggle-caret {
+      padding-right: 6px; 
+    }
 
     &.file-title-clear {
       padding-left: 0;
diff --git a/app/views/projects/diffs/_content.html.haml b/app/views/projects/diffs/_content.html.haml
index d37961c4e40..779c8ea0104 100644
--- a/app/views/projects/diffs/_content.html.haml
+++ b/app/views/projects/diffs/_content.html.haml
@@ -11,7 +11,9 @@
     - elsif diff_file.collapsed?
       - url = url_for(params.merge(action: :diff_for_path, old_path: diff_file.old_path, new_path: diff_file.new_path))
       .nothing-here-block.diff-collapsed{data: { diff_for_path: url } }
-        This diff is collapsed. Click to expand it.
+        This diff is collapsed.
+        %a.click-to-expand
+          Click to expand it.
     - elsif diff_file.diff_lines.length > 0
       - if diff_view == :parallel
         = render "projects/diffs/parallel_view", diff_file: diff_file, project: project, blob: blob
diff --git a/app/views/projects/diffs/_file_header.html.haml b/app/views/projects/diffs/_file_header.html.haml
index 95a2772fd0b..a6a2e5690b5 100644
--- a/app/views/projects/diffs/_file_header.html.haml
+++ b/app/views/projects/diffs/_file_header.html.haml
@@ -1,3 +1,4 @@
+%i.fa.diff-toggle-caret
 - if defined?(blob) && blob && diff_file.submodule?
   %span
     = icon('archive fw')