Add convenience versions of HttpHeaders::set() and add() that take ownership.

c++/src/kj/compat/http.c++

@@ -328,6 +328,11 @@ void HttpHeaders::set(HttpHeaderId id, kj::StringPtr value) {
   indexedHeaders[id.id] = value;
 }
 
+void HttpHeaders::set(HttpHeaderId id, kj::String&& value) {
+  set(id, kj::StringPtr(value));
+  takeOwnership(kj::mv(value));
+}
+
 void HttpHeaders::add(kj::StringPtr name, kj::StringPtr value) {
   requireValidHeaderName(name);
   requireValidHeaderValue(value);
@@ -336,6 +341,17 @@ void HttpHeaders::add(kj::StringPtr name, kj::StringPtr value) {
       "can't set connection-level headers on HttpHeaders", name, value) { break; }
 }
 
+void HttpHeaders::add(kj::StringPtr name, kj::String&& value) {
+  add(name, kj::StringPtr(value));
+  takeOwnership(kj::mv(value));
+}
+
+void HttpHeaders::add(kj::String&& name, kj::String&& value) {
+  add(kj::StringPtr(name), kj::StringPtr(value));
+  takeOwnership(kj::mv(name));
+  takeOwnership(kj::mv(value));
+}
+
 kj::Maybe<uint> HttpHeaders::addNoCheck(kj::StringPtr name, kj::StringPtr value) {
   KJ_IF_MAYBE(id, table->stringToId(name)) {
     if (id->id > CONNECTION_HEADER_THRESHOLD) {

c++/src/kj/compat/http.h

@@ -254,16 +254,23 @@ public:
   // to IDs in the header table. Both inputs are of type kj::StringPtr.
 
   void set(HttpHeaderId id, kj::StringPtr value);
+  void set(HttpHeaderId id, kj::String&& value);
   // Sets a header value, overwriting the existing value.
   //
+  // The String&& version is equivalent to calling the other version followed by takeOwnership().
+  //
   // WARNING: It is the caller's responsibility to ensure that `value` remains valid until the
   //   HttpHeaders object is destroyed. This allows string literals to be passed without making a
   //   copy, but complicates the use of dynamic values. Hint: Consider using `takeOwnership()`.
 
   void add(kj::StringPtr name, kj::StringPtr value);
+  void add(kj::StringPtr name, kj::String&& value);
+  void add(kj::String&& name, kj::String&& value);
   // Append a header. `name` will be looked up in the header table, but if it's not mapped, the
   // header will be added to the list of unmapped headers.
   //
+  // The String&& versions are equivalent to calling the other version followed by takeOwnership().
+  //
   // WARNING: It is the caller's responsibility to ensure that `name` and `value` remain valid
   //   until the HttpHeaders object is destroyed. This allows string literals to be passed without
   //   making a copy, but complicates the use of dynamic values. Hint: Consider using
@@ -280,8 +287,6 @@ public:
   void takeOwnership(HttpHeaders&& otherHeaders);
   // Takes overship of a string so that it lives until the HttpHeaders object is destroyed. Useful
   // when you've passed a dynamic value to set() or add() or parse*().
-  //
-  // TODO(soon): Is takeOwnership() actually needed?
 
   struct ConnectionHeaders {
     // These headers govern details of the specific HTTP connection or framing of the content.