Do not mark strip_tags result as html_safe

Thanks to Marek Labos & Nethemba

actionpack/lib/action_view/helpers/sanitize_helper.rb

@@ -72,7 +72,7 @@ def sanitize_css(style)
       #   strip_tags("<div id='top-bar'>Welcome to my website!</div>")
       #   # => Welcome to my website!
       def strip_tags(html)
-        self.class.full_sanitizer.sanitize(html).try(:html_safe)
+        self.class.full_sanitizer.sanitize(html)
       end
 
       # Strips all link tags from +text+ leaving just the link text.

actionpack/test/template/sanitize_helper_test.rb

@@ -42,9 +42,9 @@ def test_strip_tags
     [nil, '', '   '].each do |blank|
       stripped = strip_tags(blank)
       assert_equal blank, stripped
-      assert stripped.html_safe? unless blank.nil?
     end
-    assert strip_tags("<script>").html_safe?
+    assert_equal "", strip_tags("<script>")
+    assert_equal "something &lt;img onerror=alert(1337)", ERB::Util.html_escape(strip_tags("something <img onerror=alert(1337)"))
   end
 
   def test_sanitize_is_marked_safe