Convert enable_bidirectional_stream into build flag local to net.

net/http/bidirectional_stream.h

 // Copyright 2015 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.
 
 #ifndef NET_HTTP_BIDIRECTIONAL_STREAM_H_
 #define NET_HTTP_BIDIRECTIONAL_STREAM_H_
 
 #include <stdint.h>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "net/http/bidirectional_stream_job.h"
 #include "net/http/http_stream_factory.h"
 #include "net/log/net_log.h"
 
-#if !defined(ENABLE_BIDIRECTIONAL_STREAM)
-#error Only include this if ENABLE_BIDIRECTIONAL_STREAM is defined

[Nico, 2015/12/30 22:36:21]

This is still important, else we'll get linker errors on bots building with
-frtti if someone includes this file without checking for the define.

[mef, 2015/12/30 23:20:46]

Ack, I'm open for suggestions.

[Nico, 2015/12/30 23:25:32]

"Don't remove this"? :-) What breaks if you keep it?

[mef, 2015/12/30 23:42:04]

Compilation of components/cronet because it has to include this file for
definition of BidirectionalStream::Delegate, yet it does not know about
net::ENABLE_BIDIRECTIONAL_STREAM build flag.

[mmenke, 2016/01/04 18:43:13]

The code to declare the build flag is a "public" dependency...  I assume that
means there's some way cronet can transitively access the build flag?  If not,
why is it a public and not a private dependency?

[mef, 2016/01/04 20:19:54]

Hrm, IIUIC move of enable_bidirectional_stream flag from base/common.gypi into
net.gypi made it essentially a private net/ flag and is not accessible from
other targets. 

I've added a separate cronet::enable_bidirectional_stream flag which doesn't
depend on net::enable_bidirectional_stream flag.

Is there some way to define a private dependency of
cronet::enable_bidirectional_stream on net::enable_bidirectional_stream flag?

-#endif
-
 class GURL;
 
 namespace net {
 
 class HttpAuthController;
 class HttpNetworkSession;
 class HttpStream;
 class HttpStreamRequest;
 class IOBuffer;
 class ProxyInfo;
@@ skipping 171 matching lines @@
   // The underlying BidirectioanlStreamJob used for this stream. It is non-NULL,
   // if the |stream_request_| successfully finishes.
   scoped_ptr<BidirectionalStreamJob> stream_job_;
 
   DISALLOW_COPY_AND_ASSIGN(BidirectionalStream);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_BIDIRECTIONAL_STREAM_H_