Remove about:flags#enable-spdy4 flag.

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 1c9ccbeec1efe3ab70c3400aa26021323ea69fad..e66ff6e36a259413c7d3e799df135c60515f6b90 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -809,11 +809,12 @@ const Experiment kExperiments[] = {
                               switches::kDisableQuic)
   },
   {
-    "enable-spdy4",
+    "enable-http2",
     IDS_FLAGS_ENABLE_SPDY4_NAME,
     IDS_FLAGS_ENABLE_SPDY4_DESCRIPTION,
     kOsAll,
-    SINGLE_VALUE_TYPE(switches::kEnableSpdy4)
+    ENABLE_DISABLE_VALUE_TYPE(switches::kEnableSpdy4,
+                              switches::kEnableNpnHttpOnly)

[Ryan Hamilton, 2015/05/11 18:05:20]

Why does kEnableNpnHttpOnly represent "disabled"? Do we have no other disable
spdy flag?

Does disabling SPDY/4 aka HTTP/2 imply disabling SPDY/3.1?

I think I'm a bit unclear on the semantics of this flag...

[Bence, 2015/05/11 19:23:17]

Good point.  Now this flag does whatever we want it to do.  Ideally one might
want two flags, one to disable HTTP/2 only, the other to disable SPDY/3.1 only,
in such a fashion that together they disable both.  However, we do not have
corresponding command line flags, and are not planning to have those.

Do you want me to set this flag to disable HTTP/2 only?  In that case, "disable"
would enable SPDY/3.1, even if the browser is in the no-SPDY control group.  Is
that not an issue?  Or shall a separate command line flag be created that only
removes HTTP/2 from the given options without messing with SPDY/3.1?  Or shall I
just remove this flag altogether for simplicity?

   },
   {
     "disable-media-source",