Provide a way to disable Nagle's algorithm on Pepper TCP sockets.

ppapi/api/private/ppb_tcp_socket_private.idl

 /* Copyright (c) 2012 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /**
  * This file defines the <code>PPB_TCPSocket_Private</code> interface.
  */
 
 label Chrome {
   M17 = 0.3,
-  M20 = 0.4
+  M20 = 0.4,
+  M26 = 0.5

[yzshen1, 2013/02/08 21:51:11]

nit: you probably cannot get it into 26, so this should be changed to 27.

[Wez, 2013/02/10 04:47:02]

Done.

+};
+
+[assert_size(4)]
+enum PP_TCPSocketFeature_Private {
+  // Disable coalescing of small writes to make TCP segments, and instead
+  // deliver data immediately. Value type is PP_VARTYPE_BOOL.
+  PP_TCPSOCKETFEATURE_NO_DELAY = 0,

[yzshen1, 2013/02/08 21:51:11]

it seems good to comment that setting this feature after a SSL handshake is
started will fail.

[Wez, 2013/02/10 04:47:02]

Done.

+
+  // Special value used for testing. Guaranteed to fail SetSocketFeature().
+  PP_TCPSOCKETFEATURE_INVALID = -1

[yzshen1, 2013/02/08 21:51:11]

Please order them by their values.

[Wez, 2013/02/10 04:47:02]

Done.

 };
 
 /**
  * The <code>PPB_TCPSocket_Private</code> interface provides TCP socket
  * operations.
  */
 interface PPB_TCPSocket_Private {
   /**
    * Allocates a TCP socket resource.
    */
@@ skipping 104 matching lines @@
 
   /**
    * Cancels any IO that may be pending, and disconnects the socket. Any pending
    * callbacks will still run, reporting PP_Error_Aborted if pending IO was
    * interrupted. It is NOT valid to call Connect() again after a call to this
    * method. Note: If the socket is destroyed when it is still connected, then
    * it will be implicitly disconnected, so you are not required to call this
    * method.
    */
   void Disconnect([in] PP_Resource tcp_socket);
+
+  /**
+   * Sets an option on |tcp_socket|.  Supported |name| and |value| parameters
+   * are as described for PP_TCPSocketFeature_Private.  |callback| will be
+   * invoked with PP_OK if setting the option succeeds, or an error code
+   * otherwise.
+   */
+  [version=0.5]
+  int32_t SetSocketFeature([in] PP_Resource udp_socket,

[yzshen1, 2013/02/08 21:51:11]

- nit: I think SetFeature() is clear enough.
- udp_socket -> tcp_socket.

[Wez, 2013/02/10 04:47:02]

SGTM; I'd chosen the function name to match the one in UDPSocket_Private.  Since
we don't care about consistency between the APIs, I've renamed this to
SetOption() for consistency with BSD socket terminology.

+                           [in] PP_TCPSocketFeature_Private name,
+                           [in] PP_Var value,
+                           [in] PP_CompletionCallback callback);
+
 };