Reduce SpdyHeaderBlock copies with move semantics in shared code.

net/tools/quic/quic_spdy_client_stream.h

Index: net/tools/quic/quic_spdy_client_stream.h
diff --git a/net/tools/quic/quic_spdy_client_stream.h b/net/tools/quic/quic_spdy_client_stream.h
index 9dac6c020ad5297d9b1cd91e30f5c7ab4b0536d7..04eb4932620d2fd636b645432a8f241d2c46507e 100644
--- a/net/tools/quic/quic_spdy_client_stream.h
+++ b/net/tools/quic/quic_spdy_client_stream.h
@@ -59,9 +59,7 @@ class QuicSpdyClientStream : public QuicSpdyStream {
 
   // Serializes the headers and body, sends it to the server, and
   // returns the number of bytes sent.
-  size_t SendRequest(const SpdyHeaderBlock& headers,
-                     base::StringPiece body,
-                     bool fin);
+  size_t SendRequest(SpdyHeaderBlock headers, base::StringPiece body, bool fin);
 
   // Returns the response data.
   const std::string& data() { return data_; }