Aria labels on top header links

Closes #12797

app/helpers/projects_helper.rb

@@ -60,7 +60,7 @@ module ProjectsHelper
     project_link = link_to simple_sanitize(project.name), project_path(project), { class: "project-item-select-holder" }
 
     if current_user
-      project_link << icon("chevron-down", class: "dropdown-toggle-caret js-projects-dropdown-toggle", data: { target: ".js-dropdown-menu-projects", toggle: "dropdown" })
+      project_link << icon("chevron-down", class: "dropdown-toggle-caret js-projects-dropdown-toggle", aria: { label: "Toggle switch project dropdown" }, data: { target: ".js-dropdown-menu-projects", toggle: "dropdown" })
     end
 
     full_title = "#{namespace_link} / #{project_link}".html_safe

app/views/layouts/header/_default.html.haml

 %header.navbar.navbar-fixed-top.navbar-gitlab{ class: nav_header_class }
   %div{ class: fluid_layout ? "container-fluid" : "container-fluid" }
     .header-content
-      %button.side-nav-toggle{type: 'button'}
+      %button.side-nav-toggle{ type: 'button', "aria-label" => "Toggle global navigation" }
         %span.sr-only Toggle navigation
         = icon('bars')
       %button.navbar-toggle{type: 'button'}
@@ -13,25 +13,25 @@
           %li.hidden-sm.hidden-xs
             = render 'layouts/search' unless current_controller?(:search)
           %li.visible-sm.visible-xs
-            = link_to search_path, title: 'Search', data: {toggle: 'tooltip', placement: 'bottom', container: 'body'} do
+            = link_to search_path, title: 'Search', aria: { label: "Search" }, data: {toggle: 'tooltip', placement: 'bottom', container: 'body'} do
               = icon('search')
           - if current_user
             - if session[:impersonator_id]
               %li.impersonation
-                = link_to admin_impersonation_path, method: :delete, title: 'Stop Impersonation', data: { toggle: 'tooltip', placement: 'bottom', container: 'body' } do
+                = link_to admin_impersonation_path, method: :delete, title: "Stop Impersonation", aria: { label: 'Stop Impersonation' }, data: { toggle: 'tooltip', placement: 'bottom', container: 'body' } do
                   = icon('user-secret fw')
             - if current_user.is_admin?
               %li
-                = link_to admin_root_path, title: 'Admin Area', data: {toggle: 'tooltip', placement: 'bottom', container: 'body'} do
+                = link_to admin_root_path, title: 'Admin Area', aria: { label: "Admin Area" }, data: {toggle: 'tooltip', placement: 'bottom', container: 'body'} do
                   = icon('wrench fw')
             %li
-              = link_to dashboard_todos_path, title: 'Todos', data: {toggle: 'tooltip', placement: 'bottom', container: 'body'} do
+              = link_to dashboard_todos_path, title: 'Todos', aria: { label: "Todos" }, data: {toggle: 'tooltip', placement: 'bottom', container: 'body'} do
                 = icon('bell fw')
                 %span.badge.todos-pending-count{ class: ("hidden" if todos_pending_count == 0) }
                   = todos_pending_count
             - if current_user.can_create_project?
               %li
-                = link_to new_project_path, title: 'New project', data: {toggle: 'tooltip', placement: 'bottom', container: 'body'} do
+                = link_to new_project_path, title: 'New project', aria: { label: "New project" }, data: {toggle: 'tooltip', placement: 'bottom', container: 'body'} do
                   = icon('plus fw')
             - if Gitlab::Sherlock.enabled?
               %li
@@ -45,12 +45,12 @@
               .dropdown-menu-nav.dropdown-menu-align-right
                 %ul
                   %li
-                    = link_to "Profile", current_user, class: 'profile-link', data: { user: current_user.username }
+                    = link_to "Profile", current_user, class: 'profile-link', aria: { label: "Profile" }, data: { user: current_user.username }
                   %li
-                    = link_to "Profile Settings", profile_path
+                    = link_to "Profile Settings", profile_path, aria: { label: "Profile Settings" }
                   %li.divider
                   %li
-                    = link_to "Sign out", destroy_user_session_path, method: :delete, class: "sign-out-link", title: 'Sign out'
+                    = link_to "Sign out", destroy_user_session_path, method: :delete, class: "sign-out-link", aria: { label: "Sign out" }
           - else
             %li
               %div