Move header-ordering validation from hpack decoder to header validator.

net/spdy/header_coalescer.cc

Index: net/spdy/header_coalescer.cc
diff --git a/net/spdy/header_coalescer.cc b/net/spdy/header_coalescer.cc
index c3af46f5cb92087ce5563a1a8c7d34f35fb7c8a2..d4faa4fc056b7052fbf9a35d340a87e2583d4c53 100644
--- a/net/spdy/header_coalescer.cc
+++ b/net/spdy/header_coalescer.cc
@@ -11,8 +11,9 @@ namespace net {
 const size_t kMaxHeaderListSize = 256 * 1024;
 
 void HeaderCoalescer::OnHeader(base::StringPiece key, base::StringPiece value) {
-  if (error_seen_)
+  if (error_seen_) {
     return;
+  }
 
   if (key.empty()) {
     DVLOG(1) << "Header name must not be empty.";
@@ -27,6 +28,15 @@ void HeaderCoalescer::OnHeader(base::StringPiece key, base::StringPiece value) {
     return;
   }
 
+  if (key[0] == ':') {
+    if (protocol_version_ == HTTP2 && regular_header_seen_) {
+      error_seen_ = true;
+      return;
+    }
+  } else {
+    regular_header_seen_ = true;
+  }
+
   auto iter = headers_.find(key);
   if (iter == headers_.end()) {
     headers_[key] = value;