GN: Replace vector<ParseNode*> with vector<unique_ptr<ParseNode>> in parse_tree.h.

tools/gn/parser.cc

Index: tools/gn/parser.cc
diff --git a/tools/gn/parser.cc b/tools/gn/parser.cc
index 33abfd0b2f0e7378c5b11cb8dde83ac60d5684a5..977ddad6e7b27d592bc1c09a574a8ebf9fdaa42f 100644
--- a/tools/gn/parser.cc
+++ b/tools/gn/parser.cc
@@ -671,7 +671,7 @@ void Parser::TraverseOrder(const ParseNode* root,
       TraverseOrder(binop->right(), pre, post);
     } else if (const BlockNode* block = root->AsBlock()) {
       for (const auto& statement : block->statements())
-        TraverseOrder(statement, pre, post);
+        TraverseOrder(statement.get(), pre, post);
       TraverseOrder(block->End(), pre, post);
     } else if (const ConditionNode* condition = root->AsConditionNode()) {
       TraverseOrder(condition->condition(), pre, post);
@@ -684,7 +684,7 @@ void Parser::TraverseOrder(const ParseNode* root,
       // Nothing.
     } else if (const ListNode* list = root->AsList()) {
       for (const auto& node : list->contents())
-        TraverseOrder(node, pre, post);
+        TraverseOrder(node.get(), pre, post);
       TraverseOrder(list->End(), pre, post);
     } else if (root->AsLiteral()) {
       // Nothing.