Fix classes that have too many virtuals for inline constructors.

net/tools/flip_server/mem_cache.cc

Index: net/tools/flip_server/mem_cache.cc
diff --git a/net/tools/flip_server/mem_cache.cc b/net/tools/flip_server/mem_cache.cc
index 950a1a6056ed06dd6a0fd22b031e96ac3c6c0704..b6728b0951e85bad94cd3aa6a7aa0aff826faac6 100644
--- a/net/tools/flip_server/mem_cache.cc
+++ b/net/tools/flip_server/mem_cache.cc
@@ -29,6 +29,8 @@ const char FLAGS_cache_base_dir[] = ".";
 
 namespace net {
 
+StoreBodyAndHeadersVisitor::StoreBodyAndHeadersVisitor() = default;
+
 void StoreBodyAndHeadersVisitor::ProcessBodyData(const char* input,
                                                  size_t size) {
   body.append(input, size);