Remove the has_body flag from write_headers.

It was only used client-side and we can infer whether we need to add
a framing mechanism from the method instead.

tornado/http1connection.py

@@ -267,21 +267,19 @@ def set_max_body_size(self, max_body_size):
         """
         self._max_body_size = max_body_size
 
-    def write_headers(self, start_line, headers, chunk=None, callback=None,
-                      has_body=True):
+    def write_headers(self, start_line, headers, chunk=None, callback=None):
         """Implements `.HTTPConnection.write_headers`."""
         if self.is_client:
             self._request_start_line = start_line
             # Client requests with a non-empty body must have either a
             # Content-Length or a Transfer-Encoding.
             self._chunking_output = (
-                has_body and
+                start_line.method in ('POST', 'PUT', 'PATCH') and
                 'Content-Length' not in headers and
                 'Transfer-Encoding' not in headers)
         else:
             self._response_start_line = start_line
             self._chunking_output = (
-                has_body and
                 # TODO: should this use
                 # self._request_start_line.version or
                 # start_line.version?

tornado/httputil.py

@@ -532,8 +532,7 @@ class HTTPConnection(object):
 
     .. versionadded:: 3.3
     """
-    def write_headers(self, start_line, headers, chunk=None, callback=None,
-                      has_body=True):
+    def write_headers(self, start_line, headers, chunk=None, callback=None):
         """Write an HTTP header block.
 
         :arg start_line: a `.RequestStartLine` or `.ResponseStartLine`.
@@ -542,9 +541,6 @@ def write_headers(self, start_line, headers, chunk=None, callback=None,
             so that small responses can be written in the same call as their
             headers.
         :arg callback: a callback to be run when the write is complete.
-        :arg bool has_body: may be false to indicate that this message
-            has no body (and so does not need either a Content-Length
-            or Transfer-Encoding)
 
         Returns a `.Future` if no callback is given.
         """

tornado/simple_httpclient.py

@@ -345,10 +345,7 @@ def _on_connect(self):
             self._sockaddr)
         start_line = httputil.RequestStartLine(self.request.method,
                                                req_path, 'HTTP/1.1')
-        self.connection.write_headers(
-            start_line, self.request.headers,
-            has_body=(self.request.body is not None or
-                      self.request.body_producer is not None))
+        self.connection.write_headers(start_line, self.request.headers)
         if self.request.expect_100_continue:
             self._read_response()
         else:

tornado/wsgi.py

@@ -99,8 +99,7 @@ def set_close_callback(self, callback):
         # so we can simply ignore the callback.
         pass
 
-    def write_headers(self, start_line, headers, chunk=None, callback=None,
-                      has_body=True):
+    def write_headers(self, start_line, headers, chunk=None, callback=None):
         if self.method == 'HEAD':
             self._expected_content_remaining = 0
         elif 'Content-Length' in headers: