Async revalidation only applies to GET methods.

net/http/http_cache_transaction.cc

Index: net/http/http_cache_transaction.cc
diff --git a/net/http/http_cache_transaction.cc b/net/http/http_cache_transaction.cc
index 9dd8458e2e27560e2e40d3bc90eb712d354c4d71..29f67d45c7e61c3486ab602fc1df33fc9be8b850 100644
--- a/net/http/http_cache_transaction.cc
+++ b/net/http/http_cache_transaction.cc
@@ -2358,8 +2358,8 @@ ValidationType HttpCache::Transaction::RequiresValidation() {
                                             cache_->clock_->Now());
 
   if (validation_required_by_headers == VALIDATION_ASYNCHRONOUS) {
-    // Asynchronous revalidation is only supported for GET and HEAD methods.
-    if (request_->method != "GET" && request_->method != "HEAD")
+    // Asynchronous revalidation is only supported for GET methods.
+    if (request_->method != "GET")
       return VALIDATION_SYNCHRONOUS;
   }