net: add a test to ensure that our TLS handshake doesn't get too large.

net/tools/testserver/testserver.py

Index: net/tools/testserver/testserver.py
diff --git a/net/tools/testserver/testserver.py b/net/tools/testserver/testserver.py
index 77a314263001a60d083f5ed0f23e9c563cd42c76..0c4369930e2cb44937e486111d6ce6996e9a396d 100755
--- a/net/tools/testserver/testserver.py
+++ b/net/tools/testserver/testserver.py
@@ -274,6 +274,7 @@ class TestPageHandler(testserver_base.BasePageHandler):
       self.ClientRedirectHandler,
       self.MultipartHandler,
       self.GetSSLSessionCacheHandler,
+      self.GetSSLClientHelloSizeHandler,
       self.SSLManySmallRecords,
       self.GetChannelID,
       self.CloseSocketHandler,
@@ -1389,6 +1390,20 @@ class TestPageHandler(testserver_base.BasePageHandler):
                        ' this request')
     return True
 
+  def GetSSLClientHelloSizeHandler(self):
+    """Send a reply containing the length of the ClientHello record."""
+
+    if not self._ShouldHandleRequest('/client-hello-length'):
+      return False
+
+    self.send_response(200)
+    self.send_header('Content-Type', 'text/plain')
+    self.end_headers()
+
+    self.wfile.write('%d' % self.server.tlsConnection.client_hello_length)
+
+    return True
+
   def SSLManySmallRecords(self):
     """Sends a reply consisting of a variety of small writes. These will be
     translated into a series of small SSL records when used over an HTTPS