SPDY - add support for spdy/2.1 to support flow control.

1) Add spdy/2.1 as a supported NPN protocol.
2) Advertise that chrome supports spdy/2.1 when --flow-control (spdy
flag) is enabled. 
3) When SPDY protocol is negotiated, enable flow_control in
spdy_session if spdy/2.1 is negotiated as NPN protocol. 

BUG=106911
R=willchan
TEST=network unit tests and if possible test with SPDY 2.1 server
with command line flag --flow-control.

This CL is same as the following CL. Implemented changes suggested
by willchan in the following review.
http://codereview.chromium.org/8890044/
Review URL: http://codereview.chromium.org/8892026

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@113942 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 11 insertions, 3 deletions

diff --git a/net/spdy/spdy_session.h b/net/spdy/spdy_session.h
index a05bd3c..3da2f1e 100644
--- a/net/spdy/spdy_session.h
+++ b/net/spdy/spdy_session.h
@@ -149,9 +149,9 @@ class NET_EXPORT SpdySession : public base::RefCounted<SpdySession>,
   static void SetSSLMode(bool enable) { use_ssl_ = enable; }
   static bool SSLMode() { return use_ssl_; }
 
-  // Enable or disable flow control.
-  static void set_flow_control(bool enable) { use_flow_control_ = enable; }
-  static bool flow_control() { return use_flow_control_; }
+  // Enable or disable flow control used by unit tests. This only applies for
+  // new SpdySessions.
+  static void set_use_flow_control(bool enable) { use_flow_control_ = enable; }
 
   // Sets the max concurrent streams per session, as a ceiling on any server
   // specific SETTINGS value.
@@ -224,6 +224,11 @@ class NET_EXPORT SpdySession : public base::RefCounted<SpdySession>,
       return unclaimed_pushed_streams_.size();
   }
 
+  // Returns true if flow control is enabled for the session.
+  bool is_flow_control_enabled() const {
+    return flow_control_;
+  }
+
   const BoundNetLog& net_log() const { return net_log_; }
 
   int GetPeerAddress(AddressList* address) const;
@@ -540,6 +545,9 @@ class NET_EXPORT SpdySession : public base::RefCounted<SpdySession>,
   // waste of effort (and MUST not be done).
   bool need_to_send_ping_;
 
+  // Indicate if flow control is enabled or not.
+  bool flow_control_;
+
   // Initial send window size for the session; can be changed by an
   // arriving SETTINGS frame; newly created streams use this value for the
   // initial send window size.