Move some SpdyHeaderBlock instances from heap to stack.

net/spdy/spdy_proxy_client_socket.cc

Index: net/spdy/spdy_proxy_client_socket.cc
diff --git a/net/spdy/spdy_proxy_client_socket.cc b/net/spdy/spdy_proxy_client_socket.cc
index 5ede10472ff7612d6ffee874cb3a3c1e70331333..ecc2912b6fde15f281a7286427eae0fd8b79b624 100644
--- a/net/spdy/spdy_proxy_client_socket.cc
+++ b/net/spdy/spdy_proxy_client_socket.cc
@@ -364,9 +364,9 @@ int SpdyProxyClientSocket::DoSendRequest() {
       base::Bind(&HttpRequestHeaders::NetLogCallback,
                  base::Unretained(&request_.extra_headers), &request_line));
 
-  std::unique_ptr<SpdyHeaderBlock> headers(new SpdyHeaderBlock());
+  SpdyHeaderBlock headers;
   CreateSpdyHeadersFromHttpRequest(request_, request_.extra_headers, true,
-                                   headers.get());
+                                   &headers);
 
   return spdy_stream_->SendRequestHeaders(std::move(headers),
                                           MORE_DATA_TO_SEND);