Make ParameterizedItem and ParameterisedIdentifier default-constructible

This makes it easier to use them in templates.

PiperOrigin-RevId: 481767941

quiche/common/structured_headers.cc

diff --git a/quiche/common/structured_headers.cc b/quiche/common/structured_headers.cc
index 3ab0058..958f627 100644
--- a/quiche/common/structured_headers.cc
+++ b/quiche/common/structured_headers.cc
@@ -746,6 +746,7 @@
   return lhs.value_ == rhs.value_;
 }
 
+ParameterizedItem::ParameterizedItem() = default;
 ParameterizedItem::ParameterizedItem(const ParameterizedItem&) = default;
 ParameterizedItem& ParameterizedItem::operator=(const ParameterizedItem&) =
     default;
@@ -774,6 +775,7 @@
       params(std::move(ps)) {}
 ParameterizedMember::~ParameterizedMember() = default;
 
+ParameterisedIdentifier::ParameterisedIdentifier() = default;
 ParameterisedIdentifier::ParameterisedIdentifier(
     const ParameterisedIdentifier&) = default;
 ParameterisedIdentifier& ParameterisedIdentifier::operator=(

quiche/common/structured_headers.h

diff --git a/quiche/common/structured_headers.h b/quiche/common/structured_headers.h
index 844f673..9d94e90 100644
--- a/quiche/common/structured_headers.h
+++ b/quiche/common/structured_headers.h
@@ -136,6 +136,7 @@
   Item identifier;
   Parameters params;
 
+  ParameterisedIdentifier();
   ParameterisedIdentifier(const ParameterisedIdentifier&);
   ParameterisedIdentifier& operator=(const ParameterisedIdentifier&);
   ParameterisedIdentifier(Item, Parameters);
@@ -154,6 +155,7 @@
   Item item;
   Parameters params;
 
+  ParameterizedItem();
   ParameterizedItem(const ParameterizedItem&);
   ParameterizedItem& operator=(const ParameterizedItem&);
   ParameterizedItem(Item, Parameters);