[Cronet] Make delaying sending request headers explicit in bidirectional stream

net/http/bidirectional_stream_impl.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_IMPL_H_
 #define NET_HTTP_BIDIRECTIONAL_STREAM_IMPL_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 74 matching lines @@
 
   BidirectionalStreamImpl();
 
   // |this| should not be destroyed during Delegate::OnHeadersSent or
   // Delegate::OnDataSent.
   virtual ~BidirectionalStreamImpl();
 
   // Starts the BidirectionalStreamImpl and sends request headers.
   virtual void Start(const BidirectionalStreamRequestInfo* request_info,
                      const BoundNetLog& net_log,
-                     bool disable_auto_flush,
+                     bool delay_headers_until_next_send_data,
                      BidirectionalStreamImpl::Delegate* delegate,
                      std::unique_ptr<base::Timer> timer) = 0;
 
   // Reads at most |buf_len| bytes into |buf|. Returns the number of bytes read,
   // ERR_IO_PENDING if the read is to be completed asynchronously, or an error
   // code if any error occurred. If returns 0, there is no more data to read.
   // This should not be called before Delegate::OnHeadersReceived is invoked,
   // and should not be called again unless it returns with number greater than
   // 0 or until Delegate::OnDataRead is invoked.
   virtual int ReadData(IOBuffer* buf, int buf_len) = 0;
@@ skipping 29 matching lines @@
   // not associated with any stream, and are not included in this value.
   virtual int64_t GetTotalSentBytes() const = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(BidirectionalStreamImpl);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_BIDIRECTIONAL_STREAM_IMPL_H_