[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 25 matching lines @@
   class NET_EXPORT_PRIVATE Delegate {
    public:
     Delegate();
 
     // Called when the stream is ready for reading and writing.
     // The delegate may call BidirectionalStreamImpl::ReadData to start reading,
     // call BidirectionalStreamImpl::SendData to send data,
     // or call BidirectionalStreamImpl::Cancel to cancel the stream.
     // The delegate should not call BidirectionalStreamImpl::Cancel
     // during this callback.
-    virtual void OnStreamReady() = 0;
+    // |request_headers_sent| if true, request headers have been sent. If false,
+    // SendRequestHeaders() needs to be explicitly called.
+    virtual void OnStreamReady(bool request_headers_sent) = 0;
 
     // Called when response headers are received.
     // This is called at most once for the lifetime of a stream.
     // The delegate may call BidirectionalStreamImpl::ReadData to start
     // reading, call BidirectionalStreamImpl::SendData to send data,
     // or call BidirectionalStreamImpl::Cancel to cancel the stream.
     virtual void OnHeadersReceived(const SpdyHeaderBlock& response_headers) = 0;
 
     // Called when read is completed asynchronously. |bytes_read| specifies how
     // much data is available.
@@ skipping 26 matching lines @@
     DISALLOW_COPY_AND_ASSIGN(Delegate);
   };
 
   BidirectionalStreamImpl();
 
   // |this| should not be destroyed during Delegate::OnHeadersSent or
   // Delegate::OnDataSent.
   virtual ~BidirectionalStreamImpl();
 
   // Starts the BidirectionalStreamImpl and sends request headers.
+  // |send_request_headers_automatically| if true, request headers will be sent
+  // automatically when stream is negotiated. If false, request headers will be
+  // sent only when SendRequestHeaders() is invoked or with next
+  // SendData/SendvData.
   virtual void Start(const BidirectionalStreamRequestInfo* request_info,
                      const BoundNetLog& net_log,
-                     bool disable_auto_flush,
+                     bool send_request_headers_automatically,
                      BidirectionalStreamImpl::Delegate* delegate,
                      std::unique_ptr<base::Timer> timer) = 0;
 
+  // Sends request headers to server.
+  // When |send_request_headers_automatically_| is
+  // false and OnStreamReady() is invoked with request_headers_sent = false,
+  // headers will be combined with next SendData/SendvData unless this
+  // method is called first, in which case headers will be sent separately
+  // without delay.
+  // (This method cannot be called when |send_request_headers_automatically_| is
+  // true nor when OnStreamReady() is invoked with request_headers_sent = true,
+  // since headers have been sent by the stream when stream is negotiated
+  // successfully.)
+  virtual void SendRequestHeaders() = 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;
 
   // Sends data. This should not be called be called before
   // Delegate::OnHeadersSent is invoked, and should not be called again until
@@ skipping 26 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_