Add brotli content-encoding filter.

chrome/browser/io_thread.cc

Index: chrome/browser/io_thread.cc
diff --git a/chrome/browser/io_thread.cc b/chrome/browser/io_thread.cc
index 35ed57e46105cec561116b820744ba8a09afa885..d07ac7ce1b9dfc3ab6668827738f69441751d50e 100644
--- a/chrome/browser/io_thread.cc
+++ b/chrome/browser/io_thread.cc
@@ -813,6 +813,7 @@ void IOThread::Init() {
           switches::kEnableUserAlternateProtocolPorts)) {
     globals_->enable_user_alternate_protocol_ports = true;
   }
+  globals_->enable_brotli.set(ShouldEnableBrotli(command_line));
   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
   // is fixed.
   tracked_objects::ScopedTracker tracking_profile13(
@@ -1087,6 +1088,8 @@ void IOThread::InitializeNetworkSessionParamsFromGlobals(
 
   globals.enable_npn.CopyToIfSet(&params->enable_npn);
 
+  globals.enable_brotli.CopyToIfSet(&params->enable_brotli);
+
   globals.enable_quic.CopyToIfSet(&params->enable_quic);
   globals.enable_quic_for_proxies.CopyToIfSet(&params->enable_quic_for_proxies);
   globals.quic_always_require_handshake_confirmation.CopyToIfSet(
@@ -1295,6 +1298,12 @@ void IOThread::ConfigureQuicGlobals(
   }
 }
 
+bool IOThread::ShouldEnableBrotli(const base::CommandLine& command_line) {
+  if (command_line.HasSwitch(switches::kDisableBrotli))
+    return false;
+  return command_line.HasSwitch(switches::kEnableBrotli);

[xunjieli, 2015/11/17 16:16:12]

Why do we have both the enable and disable switches?

[eustas, 2015/11/17 17:57:20]

This makes rolling out feature easier. User have combo-box in about:flags UI
with 3 choices - default / enable / disable.
On the first stage, feature is disabled by default and experienced users can
enable it. On the later stages this leaves user ability to disable the feature
(when it will be enabled by default).

+}
+
 bool IOThread::ShouldEnableQuic(const base::CommandLine& command_line,
                                 base::StringPiece quic_trial_group,
                                 bool quic_allowed_by_policy) {