Add back pipelining after M17 branch point.

Revert 113035 - Remove HTTP Pipelining from about:flags, and the command
line switch for M17, as the branch point is tonight.

This will be reverted after the branch point.

BUG=106313

Review URL: http://codereview.chromium.org/8799013

Review URL: http://codereview.chromium.org/8771048

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@114025 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/about_flags.cc

@@ -372,6 +372,13 @@ const Experiment kExperiments[] = {
     kOsAll,
     SINGLE_VALUE_TYPE(switches::kUseMoreWebUI)
   },
+  {
+    "enable-http-pipelining",
+    IDS_FLAGS_ENABLE_HTTP_PIPELINING_NAME,
+    IDS_FLAGS_ENABLE_HTTP_PIPELINING_DESCRIPTION,
+    kOsAll,
+    SINGLE_VALUE_TYPE(switches::kEnableHttpPipelining)
+  },
   // TODO(flackr): Remove this flag and views screen locker when the WebUI
   // locker is mature (crbug.com/105263).
   {

chrome/browser/chrome_browser_main.cc

@@ -289,6 +289,9 @@ void InitializeNetworkOptions(const CommandLine& parsed_command_line) {
     // Enable WebSocket over SPDY.
     net::WebSocketJob::set_websocket_over_spdy_enabled(true);
   }
+
+  if (parsed_command_line.HasSwitch(switches::kEnableHttpPipelining))
+    net::HttpStreamFactory::set_http_pipelining_enabled(true);
 }
 
 void InitializeURLRequestThrottlerManager(net::NetLog* net_log) {

chrome/common/chrome_switches.cc

@@ -482,6 +482,11 @@ const char kEnableFastback[]                = "enable-fastback";
 // for example page cycler and layout tests. See bug 1157243.
 const char kEnableFileCookies[]             = "enable-file-cookies";
 
+// Enable HTTP pipelining. Attempt to pipeline HTTP connections. Heuristics will
+// try to figure out if pipelining can be used for a given host and request.
+// Without this flag, pipelining will never be used.
+const char kEnableHttpPipelining[]          = "enable-http-pipelining";
+
 // Enables the in-browser thumbnailing, which is more efficient than the
 // in-renderer thumbnailing, as we can use more information to determine if we
 // need to update thumbnails.

chrome/common/chrome_switches.h

@@ -140,6 +140,7 @@ extern const char kEnableExtensionAlerts[];
 extern const char kEnableExtensionTimelineApi[];
 extern const char kEnableFastback[];
 extern const char kEnableFileCookies[];
+extern const char kEnableHttpPipelining[];
 extern const char kEnableInBrowserThumbnailing[];
 extern const char kEnableIPv6[];
 extern const char kEnableIPCFuzzing[];