Refactor: move flow controller from QuicConnection to QuicSession.

net/quic/quic_session.cc

Index: net/quic/quic_session.cc
diff --git a/net/quic/quic_session.cc b/net/quic/quic_session.cc
index 6d749ec1fbeec599205908ccde20d1aecfae7687..512044f9fb4e15b20751010060ff67fa004897f7 100644
--- a/net/quic/quic_session.cc
+++ b/net/quic/quic_session.cc
@@ -8,6 +8,7 @@
 #include "net/quic/crypto/proof_verifier.h"
 #include "net/quic/quic_connection.h"
 #include "net/quic/quic_flags.h"
+#include "net/quic/quic_flow_controller.h"
 #include "net/quic/quic_headers_stream.h"
 #include "net/ssl/ssl_info.h"
 
@@ -95,6 +96,7 @@ class VisitorShim : public QuicConnectionVisitorInterface {
 };
 
 QuicSession::QuicSession(QuicConnection* connection,
+                         uint32 max_flow_control_receive_window_bytes,
                          const QuicConfig& config)
     : connection_(connection),
       visitor_shim_(new VisitorShim(this)),
@@ -105,7 +107,20 @@ QuicSession::QuicSession(QuicConnection* connection,
       error_(QUIC_NO_ERROR),
       goaway_received_(false),
       goaway_sent_(false),
-      has_pending_handshake_(false) {
+      has_pending_handshake_(false),
+      max_flow_control_receive_window_bytes_(
+          max_flow_control_receive_window_bytes) {
+  if (max_flow_control_receive_window_bytes_ < kDefaultFlowControlSendWindow) {
+    LOG(ERROR) << "Initial receive window ("
+               << max_flow_control_receive_window_bytes_
+               << ") cannot be set lower than default ("
+               << kDefaultFlowControlSendWindow << ").";
+    max_flow_control_receive_window_bytes_ = kDefaultFlowControlSendWindow;
+  }
+  flow_controller_.reset(new QuicFlowController(
+      connection_->supported_versions().front(), 0, is_server(),
+      kDefaultFlowControlSendWindow, max_flow_control_receive_window_bytes_,
+      max_flow_control_receive_window_bytes_));
 
   connection_->set_visitor(visitor_shim_.get());
   connection_->SetFromConfig(config_);
@@ -229,8 +244,7 @@ void QuicSession::OnWindowUpdateFrames(
                << "Received connection level flow control window update with "
                   "byte offset: " << frames[i].byte_offset;
       if (FLAGS_enable_quic_connection_flow_control &&
-          connection()->flow_controller()->UpdateSendWindowOffset(
-              frames[i].byte_offset)) {
+          flow_controller_->UpdateSendWindowOffset(frames[i].byte_offset)) {
         connection_window_updated = true;
       }
       continue;
@@ -399,8 +413,7 @@ void QuicSession::OnConfigNegotiated() {
     }
 
     // Update connection level window.
-    connection()->flow_controller()->UpdateSendWindowOffset(
-        new_flow_control_send_window);
+    flow_controller_->UpdateSendWindowOffset(new_flow_control_send_window);
   }
 }
 
@@ -605,4 +618,10 @@ void QuicSession::PostProcessAfterData() {
   closed_streams_.clear();
 }
 
+void QuicSession::OnSuccessfulVersionNegotiation(const QuicVersion& version) {
+  if (version < QUIC_VERSION_19) {
+    flow_controller_->Disable();
+  }
+}
+
 }  // namespace net