Get rid of websocket_over_spdy_enabled global.

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 6feb06432746c92731ce7350a7c6d9adf856bbc6..4f554291ba7b98f90db3a533483085fa0ca0991c 100644
--- a/chrome/browser/io_thread.h
+++ b/chrome/browser/io_thread.h
@@ -181,6 +181,8 @@ class IOThread : public content::BrowserThreadDelegate {
     // main frame load fails with a DNS error in order to provide more useful
     // information to the renderer so it can show a more specific error page.
     scoped_ptr<chrome_browser_net::DnsProbeService> dns_probe_service;
+
+    Optional<bool> enable_websocket_over_spdy;
   };
 
   // |net_log| must either outlive the IOThread or be NULL.