Revert of Avoids the "re-encode HPACK as SPDY3" step.

net/quic/spdy_utils.cc

Index: net/quic/spdy_utils.cc
diff --git a/net/quic/spdy_utils.cc b/net/quic/spdy_utils.cc
index bf50d7d29e1bf45cab6306084a8d4a22255d1fe0..90e65373827dc08b0052c52e8e019117d7f82813 100644
--- a/net/quic/spdy_utils.cc
+++ b/net/quic/spdy_utils.cc
@@ -117,6 +117,12 @@
     const string& name = p.first;
     if (name.empty()) {
       DVLOG(1) << "Header name must not be empty.";
+      return false;
+    }
+
+    if (std::any_of(name.begin(), name.end(), base::IsAsciiUpper<char>)) {
+      DLOG(ERROR) << "Malformed header: Header name " << name
+                  << " contains upper-case characters.";
       return false;
     }