Refactor header logo and setup expectation on it size

app/assets/stylesheets/sections/header.scss

@@ -100,18 +100,14 @@ header {
 
     a {
       float: left;
-      padding: 0px;
-      margin: 0 6px;
-
-      h1 {
-        margin: 0;
-        background: image-url('logo-black.png') no-repeat center center;
-        background-size: 32px;
-        float: left;
+      padding: 5px 0;
       height: 46px;
-        width: 40px;
-        @include header-font;
-        text-indent: -9999px;
+      width: 52px;
+      text-align: center;
+
+      img {
+        width: 36px;
+        height: 36px;
       }
     }
     &:hover {

app/assets/stylesheets/themes/dark-theme.scss

@@ -12,12 +12,6 @@
           &:hover {
             background-color: $color-darker;
           }
-
-          h1 {
-            background: image-url('logo-white.png') no-repeat center center;
-            background-size: 32px;
-            color: #FFF;
-          }
         }
 
         .app_logo {

app/helpers/appearances_helper.rb

@@ -14,4 +14,12 @@ module AppearancesHelper
   def brand_text
     nil
   end
+
+  def brand_header_logo
+    if theme_type == 'light_theme'
+      image_tag 'logo-black.png'
+    else
+      image_tag 'logo-white.png'
+    end
+  end
 end

app/views/layouts/_head_panel.html.haml

@@ -3,7 +3,7 @@
     .container
       %div.app_logo
         = link_to root_path, class: "home has_bottom_tooltip", title: "Dashboard" do
-          %h1 GITLAB
+          = brand_header_logo
       %h1.title= title
 
       %button.navbar-toggle{"data-target" => ".navbar-collapse", "data-toggle" => "collapse", type: "button"}

app/views/layouts/_public_head_panel.html.haml

@@ -2,10 +2,8 @@
   .navbar-inner
     .container
       %div.app_logo
-        %span.separator
         = link_to explore_root_path, class: "home" do
-          %h1 GITLAB
-        %span.separator
+          = brand_header_logo
       %h1.title= title
 
       %button.navbar-toggle{"data-target" => ".navbar-collapse", "data-toggle" => "collapse", type: "button"}