Change reply button to text field

app/assets/stylesheets/pages/note_form.scss

@@ -5,6 +5,11 @@
   @extend .btn-primary;
   margin: 10px $gl-padding;
 }
+
+.comment-btn {
+  @extend .btn-create;
+}
+
 .diff-file .diff-content {
   tr.line_holder:hover > td .line_note_link {
     opacity: 1.0;
@@ -118,8 +123,8 @@
   }
 
   .discussion-reply-holder {
-    background: $background-color;
-    border-top: 1px solid $border-color;
+    background-color: $white-light;
+    padding: 10px 16px;
   }
 }
 
@@ -183,3 +188,12 @@
     float: left;
   }
 }
+
+.note-reply-field {
+  background-color: $background-color;
+
+  &:focus {
+    box-shadow: none;
+    border-color: $border-color;
+  }
+}

app/helpers/notes_helper.rb

@@ -69,10 +69,8 @@ module NotesHelper
       line_type:     line_type
     }
 
-    button_tag class: 'btn btn-nr reply-btn js-discussion-reply-button',
-               data: data, title: 'Add a reply' do
-      link_text = icon('comment')
-      link_text << ' Reply'
-    end
+    text_field_tag 'reply-field', nil, placeholder: 'Reply...',
+                    class: 'form-control note-reply-field js-discussion-reply-button',
+                    data: data
   end
 end