Throttle HttpStreamFactoryImpl::Job to HTTP/2-supported servers

net/spdy/chromium/spdy_session_pool.h

 // 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.
 
 #ifndef NET_SPDY_CHROMIUM_SPDY_SESSION_POOL_H_
 #define NET_SPDY_CHROMIUM_SPDY_SESSION_POOL_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 161 matching lines @@
   // proxy.
   void OnNewSpdySessionReady(const base::WeakPtr<SpdySession>& spdy_session,
                              bool direct,
                              const SSLConfig& used_ssl_config,
                              const ProxyInfo& used_proxy_info,
                              bool was_alpn_negotiated,
                              NextProto negotiated_protocol,
                              bool using_spdy,
                              NetLogSource source_dependency);
 
+  // Called when a HttpStreamRequest is started with |spdy_session_key|.
+  // Returns true if the request should continue. Returns false if the request
+  // should wait until |callback| is invoked before continuing.
+  bool StartRequest(const SpdySessionKey& spdy_session_key,

[Bence, 2017/06/09 19:17:40]

Optional: return OK instead of true and discard |callback|, or ERR_IO_PENDING
instead of false and call |callback| later, just like it's done elsewhere in the
network stack.

[xunjieli, 2017/06/13 15:23:11]

Acknowledged. But the callback is not a net::CompletionCallback. I will keep it
as it is so it's easier to think about the return value. Change it to return a
net_error code, the caller might add error handling code for non-OK and
non-ERR_IO_PENDING.

+                    const base::Closure& callback);
+
+  // Resumes all pending requests with |spdy_session_key|.
+  void ResumeAllPendingRequests(const SpdySessionKey& spdy_session_key);
+  // Resumes the next pending request with |spdy_session_key|.
+  void ResumeNextPendingRequest(const SpdySessionKey& spdy_session_key);

[Bence, 2017/06/09 19:17:40]

Do you think it is worth making this method private, or inlining it, since there
is only one call site?

[xunjieli, 2017/06/13 15:23:11]

Done.

+
   // Adds |request| to |spdy_session_request_map_| under |spdy_session_key| Key.
   // Sets |spdy_session_key| as |request|'s SpdySessionKey.
   void AddRequestToSpdySessionRequestMap(
       const SpdySessionKey& spdy_session_key,
       HttpStreamFactoryImpl::Request* request);
 
   // Removes |request| from |spdy_session_request_map_|. No-op if |request| does
   // not have a SpdySessionKey.
   void RemoveRequestFromSpdySessionRequestMap(
       HttpStreamFactoryImpl::Request* request);
@@ skipping 72 matching lines @@
   bool enable_ping_based_connection_checking_;
 
   size_t session_max_recv_window_size_;
 
   // Settings that are sent in the initial SETTINGS frame
   // (if |enable_sending_initial_data_| is true),
   // and also control SpdySession parameters like initial receive window size
   // and maximum HPACK dynamic table size.
   const SettingsMap initial_settings_;
 
+  // TODO(xunjieli): Merge these two.
   SpdySessionRequestMap spdy_session_request_map_;
+  typedef std::map<SpdySessionKey, std::list<base::Closure>>
+      SpdySessionPendingRequestMap;
+  SpdySessionPendingRequestMap spdy_session_pending_request_map_;
 
   TimeFunc time_func_;
   ServerPushDelegate* push_delegate_;
 
   // Determines if a proxy is a trusted SPDY proxy, which is allowed to push
   // resources from origins that are different from those of their associated
   // streams. May be nullptr.
   ProxyDelegate* proxy_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(SpdySessionPool);
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_CHROMIUM_SPDY_SESSION_POOL_H_