[py3] Fixed regression introduced in 536b030363.

Refs #18764.

Reverted 536b030363 and switched to a more explicit way of avoiding
calling bytes(<int>).

This definitely deserves a refactoring. Specifically, _get_content
should just return b''.join(self). Unfortunately that's impossible
with the current tests.

django/http/__init__.py

@@ -85,7 +85,7 @@ from django.core.files import uploadhandler
 from django.http.multipartparser import MultiPartParser
 from django.http.utils import *
 from django.utils.datastructures import MultiValueDict, ImmutableList
-from django.utils.encoding import force_bytes, force_text, iri_to_uri, smart_bytes, smart_str
+from django.utils.encoding import smart_bytes, smart_str, iri_to_uri, force_text
 from django.utils.http import cookie_date
 from django.utils import six
 from django.utils import timezone
@@ -670,12 +670,16 @@ class HttpResponse(object):
                         expires='Thu, 01-Jan-1970 00:00:00 GMT')
 
     def _get_content(self):
-        # The logic below obeys the following constraints:
-        # - do not perform any encoding if a Content-Encoding is set (#4969)
-        # - force string conversion of non-string types (#16494)
-        # - avoid simply calling bytes() with Python 3 (#18764)
-        encoding = 'ascii' if self.has_header('Content-Encoding') else self._charset
-        return b''.join(force_bytes(e, encoding) for e in self._container)
+        if self.has_header('Content-Encoding'):
+            def make_bytes(value):
+                if isinstance(value, int):
+                    return six.text_type(value).encode()
+                elif isinstance(value, six.text_type):
+                    return value.encode('ascii')
+                else:
+                    return bytes(value)
+            return b''.join(make_bytes(e) for e in self._container)
+        return b''.join(smart_bytes(e, self._charset) for e in self._container)
 
     def _set_content(self, value):
         if hasattr(value, '__iter__') and not isinstance(value, (bytes, six.string_types)):
@@ -692,9 +696,12 @@ class HttpResponse(object):
         return self
 
     def __next__(self):
-        # Use the same logic as _get_content.
-        encoding = 'ascii' if self.has_header('Content-Encoding') else self._charset
-        return force_bytes(next(self._iterator), encoding)
+        chunk = next(self._iterator)
+        if isinstance(chunk, int):
+            return six.text_type(chunk).encode()
+        if isinstance(chunk, six.text_type):
+            return chunk.encode(self._charset)
+        return bytes(chunk)
 
     next = __next__             # Python 2 compatibility