diff --git a/spdy/core/spdy_protocol.cc b/spdy/core/spdy_protocol.cc
index 2116025..b1d9f56 100644
--- a/spdy/core/spdy_protocol.cc
+++ b/spdy/core/spdy_protocol.cc
@@ -60,7 +60,31 @@
 }
 
 bool IsDefinedFrameType(uint8_t frame_type_field) {
-  return frame_type_field <= SerializeFrameType(SpdyFrameType::MAX_FRAME_TYPE);
+  switch (static_cast<SpdyFrameType>(frame_type_field)) {
+    case SpdyFrameType::DATA:
+      return true;
+    case SpdyFrameType::HEADERS:
+      return true;
+    case SpdyFrameType::PRIORITY:
+      return true;
+    case SpdyFrameType::RST_STREAM:
+      return true;
+    case SpdyFrameType::SETTINGS:
+      return true;
+    case SpdyFrameType::PUSH_PROMISE:
+      return true;
+    case SpdyFrameType::PING:
+      return true;
+    case SpdyFrameType::GOAWAY:
+      return true;
+    case SpdyFrameType::WINDOW_UPDATE:
+      return true;
+    case SpdyFrameType::CONTINUATION:
+      return true;
+    case SpdyFrameType::ALTSVC:
+      return true;
+  }
+  return false;
 }
 
 SpdyFrameType ParseFrameType(uint8_t frame_type_field) {
diff --git a/spdy/core/spdy_protocol.h b/spdy/core/spdy_protocol.h
index 175db51..39b3daa 100644
--- a/spdy/core/spdy_protocol.h
+++ b/spdy/core/spdy_protocol.h
@@ -99,7 +99,6 @@
   CONTINUATION = 0x09,
   // ALTSVC is a public extension.
   ALTSVC = 0x0a,
-  MAX_FRAME_TYPE = ALTSVC,
 };
 
 // Flags on data packets.