Wait for viewers to load

Adds qa-spinner class and wait for it to go away
before making assertions.

app/views/projects/blob/viewers/_loading.html.haml

 .text-center.prepend-top-default.append-bottom-default
-  = icon('spinner spin 2x', 'aria-hidden' => 'true', 'aria-label' => 'Loading content…')
+  = icon('spinner spin 2x', 'aria-hidden' => 'true', 'aria-label' => 'Loading content…', class: 'qa-spinner')

qa/qa/page/project/show.rb

@@ -51,6 +51,16 @@ module QA
           element :branches_dropdown
         end
 
+        view 'app/views/projects/blob/viewers/_loading.html.haml' do
+          element :spinner
+        end
+
+        def wait_for_viewers_to_load
+          wait(reload: false) do
+            has_no_element?(:spinner)
+          end
+        end
+
         def create_first_new_file!
           within_element(:quick_actions) do
             click_link_with_text 'New file'

qa/qa/specs/features/browser_ui/3_create/repository/push_http_private_token_spec.rb

@@ -22,7 +22,11 @@ module QA
         end
 
         push.project.visit!
-        Page::Project::Show.perform(&:wait_for_push)
+
+        Page::Project::Show.perform do |page|
+          page.wait_for_push
+          page.wait_for_viewers_to_load
+        end
 
         expect(page).to have_content('README.md')
         expect(page).to have_content('This is a test project')