[SPDY] Add flag and about:flags entry for SPDY/4 alpha 1

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 8993c39bca1368337fb0f6315be9892d204d73b6..e0db12f0853231a12bde83b19cd8735860da9b0c 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -629,6 +629,9 @@ const char kEnableSdch[]                    = "enable-sdch";
 // Enable SPDY/3.1. This is a temporary testing flag.
 const char kEnableSpdy31[]                  = "enable-spdy31";
 
+// Enable SPDY/4 alpha 1. This is a temporary testing flag.
+const char kEnableSpdy4a1[]                 = "enable-spdy4a1";
+
 // Enable SPDY CREDENTIAL frame support.  This is a temporary testing flag.
 const char kEnableSpdyCredentialFrames[]    = "enable-spdy-credential-frames";