Add support for setting QUIC connection options via field trial config.

chrome/browser/io_thread.h

Index: chrome/browser/io_thread.h
diff --git a/chrome/browser/io_thread.h b/chrome/browser/io_thread.h
index 2daf2befde615742932a93a2ca2d2f0a521cf217..d173d1f8320759c364634a038b26964efb6adf8f 100644
--- a/chrome/browser/io_thread.h
+++ b/chrome/browser/io_thread.h
@@ -69,6 +69,10 @@ namespace policy {
 class PolicyService;
 }  // namespace policy
 
+namespace test {
+class IOThreadPeer;
+}  // namespace test
+
 // Contains state associated with, initialized and cleaned up on, and
 // primarily used on, the IO thread.
 //
@@ -87,7 +91,7 @@ class IOThread : public content::BrowserThreadDelegate {
         set_ = true;
         value_ = value;
       }
-      void CopyToIfSet(T* value) {
+      void CopyToIfSet(T* value) const {
         if (set_) {
           *value = value_;
         }
@@ -172,9 +176,9 @@ class IOThread : public content::BrowserThreadDelegate {
     Optional<bool> enable_quic;
     Optional<bool> enable_quic_pacing;
     Optional<bool> enable_quic_time_based_loss_detection;
-    Optional<bool> enable_quic_persist_server_info;
     Optional<bool> enable_quic_port_selection;
     Optional<size_t> quic_max_packet_length;
+    net::QuicTagVector quic_connection_options;
     Optional<std::string> quic_user_agent_id;
     Optional<net::QuicVersionVector> quic_supported_versions;
     Optional<net::HostPortPair> origin_to_force_quic_on;
@@ -227,6 +231,8 @@ class IOThread : public content::BrowserThreadDelegate {
   // InitSystemRequestContext().
   friend class SystemURLRequestContextGetter;
 
+  friend class test::IOThreadPeer;
+
   // BrowserThreadDelegate implementation, runs on the IO thread.
   // This handles initialization and destruction of state that must
   // live on the IO thread.
@@ -234,6 +240,11 @@ class IOThread : public content::BrowserThreadDelegate {
   virtual void InitAsync() OVERRIDE;
   virtual void CleanUp() OVERRIDE;
 
+  // Initializes |params| based on the settings in |globals|.
+  static void InitializeNetworkSessionParamsFromGlobals(
+      const Globals& globals,
+      net::HttpNetworkSession::Params* params);
+
   void InitializeNetworkOptions(const base::CommandLine& parsed_command_line);
 
   // Enable SPDY with the given mode, which may contain the following:
@@ -277,40 +288,60 @@ class IOThread : public content::BrowserThreadDelegate {
   // well as the QUIC field trial group.
   void ConfigureQuic(const base::CommandLine& command_line);
 
+  // Configures QUIC options in |globals| based on the flags in |command_line|
+  // as well as the QUIC field trial group and parameters.
+  static void ConfigureQuicGlobals(
+      const base::CommandLine& command_line,
+      base::StringPiece quic_trial_group,

[jar (doing other things), 2014/06/20 23:25:12]

nit: should this be a const ref?

I think it is unusual in Chrome to not use const (on string pieces), but I just
noticed (looking at other code in net) that it is sometimes used without the
const.

I *think* the right thing is to use the const + ref in arg passing (as is
regularly done in string_piece.h).

same thing later in file.

[Ryan Hamilton, 2014/06/21 02:45:23]

As I understand it, it's actually faster to pass in a StringPiece by value then
it is to pass a ref. We consistently pass by value in QUIC code, fwiw.

+      const std::map<std::string, std::string>& quic_trial_params,
+      Globals* globals);
+
   // Returns true if QUIC should be enabled, either as a result
   // of a field trial or a command line flag.
-  bool ShouldEnableQuic(const base::CommandLine& command_line,
-                        base::StringPiece quic_trial_group);
+  static bool ShouldEnableQuic(
+      const base::CommandLine& command_line,
+      base::StringPiece quic_trial_group);
 
   // Returns true if the selection of the ephemeral port in bind() should be
   // performed by Chromium, and false if the OS should select the port.  The OS
   // option is used to prevent Windows from posting a security security warning
   // dialog.
-  bool ShouldEnableQuicPortSelection(const base::CommandLine& command_line);
+  static bool ShouldEnableQuicPortSelection(
+      const base::CommandLine& command_line);
 
   // Returns true if QUIC packet pacing should be negotiated during the
   // QUIC handshake.
-  bool ShouldEnableQuicPacing(const base::CommandLine& command_line,
-                              base::StringPiece quic_trial_group);
+  static bool ShouldEnableQuicPacing(
+      const base::CommandLine& command_line,
+      base::StringPiece quic_trial_group,
+      const std::map<std::string, std::string>& quic_trial_params);
 
   // Returns true if QUIC time-base loss detection should be negotiated during
   // the QUIC handshake.
-  bool ShouldEnableQuicTimeBasedLossDetection(
+  static bool ShouldEnableQuicTimeBasedLossDetection(
       const base::CommandLine& command_line,
-      base::StringPiece quic_trial_group);
-
-  // Returns true if Chromium should persist QUIC server config information to
-  // disk cache.
-  bool ShouldEnableQuicPersistServerInfo(const base::CommandLine& command_line);
+      base::StringPiece quic_trial_group,
+      const std::map<std::string, std::string>& quic_trial_params);
 
   // Returns the maximum length for QUIC packets, based on any flags in
   // |command_line| or the field trial.  Returns 0 if there is an error
   // parsing any of the options, or if the default value should be used.
-  size_t GetQuicMaxPacketLength(const base::CommandLine& command_line,
-                                base::StringPiece quic_trial_group);
+  static size_t GetQuicMaxPacketLength(
+      const base::CommandLine& command_line,
+      base::StringPiece quic_trial_group,
+      const std::map<std::string, std::string>& quic_trial_params);
 
-  // Returns the quic versions specified by any flags in |command_line|.
-  net::QuicVersion GetQuicVersion(const base::CommandLine& command_line);
+  // Returns the QUIC versions specified by any flags in |command_line|
+  // or |quic_trial_params|.
+  static net::QuicVersion GetQuicVersion(
+      const base::CommandLine& command_line,
+      const std::map<std::string, std::string>& quic_trial_params);

[jar (doing other things), 2014/06/20 23:25:12]

nit: I think it would be helpful to decide a typedef for this map.  Maybe:

FinchParameters

It is used numerous times in this file, and made reading harder (to have to
re-parse this each time).

[Ryan Hamilton, 2014/06/21 02:45:23]

Done. (Yeah, I wish there were such a typedef in the finch .h file.)

+
+  // Returns the QUIC connection options specified by any flags in
+  // |command_line| or |quic_trial_params|.
+  static net::QuicTagVector GetQuicConnectionOptions(
+      const base::CommandLine& command_line,
+      const std::map<std::string, std::string>& quic_trial_params);
 
   // The NetLog is owned by the browser process, to allow logging from other
   // threads during shutdown, but is used most frequently on the IOThread.