Refactor StringPiece hash.

net/quic/quic_blocked_writer_interface.h

Index: net/quic/quic_blocked_writer_interface.h
diff --git a/net/quic/quic_blocked_writer_interface.h b/net/quic/quic_blocked_writer_interface.h
index 78a270af12f685636bf3bf495b5965e3a9ca6ae6..a3a2622a599d561a226371b6b888b2b3e5a9903f 100644
--- a/net/quic/quic_blocked_writer_interface.h
+++ b/net/quic/quic_blocked_writer_interface.h
@@ -24,20 +24,15 @@ class NET_EXPORT_PRIVATE QuicBlockedWriterInterface {
   virtual void OnCanWrite() = 0;
 };
 
-}  // namespace net
-
-#if defined(COMPILER_GCC)
-namespace BASE_HASH_NAMESPACE {
 // Hash pointers as if they were int's, but bring more entropy to the lower
 // bits.
-template <>
-struct hash<net::QuicBlockedWriterInterface*> {
+struct QuicBlockedWriterInterfacePtrHash {
   std::size_t operator()(const net::QuicBlockedWriterInterface* ptr) const {
     size_t k = reinterpret_cast<size_t>(ptr);
     return k + (k >> 6);
   }
 };
-}
-#endif
+
+}  // namespace net
 
 #endif  // NET_QUIC_QUIC_BLOCKED_WRITER_INTERFACE_H_