Use DefaultConstructTraits for network::CorsErrorStatus.

This allows the default constructor for CorsErrorStatus to be restricted
so it is only available to Mojo.

Fixed: 1408442
Change-Id: Ia26e1689a66167d6d5ed485735509d4fd2048f70
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4129453
Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1129442}

mojo/public/cpp/bindings/lib/serialization_forward.h

@@ -10,6 +10,7 @@
 #include "mojo/public/cpp/bindings/array_traits.h"
 #include "mojo/public/cpp/bindings/enum_traits.h"
 #include "mojo/public/cpp/bindings/lib/buffer.h"
+#include "mojo/public/cpp/bindings/lib/default_construct_tag_internal.h"
 #include "mojo/public/cpp/bindings/lib/message_fragment.h"
 #include "mojo/public/cpp/bindings/lib/template_util.h"
 #include "mojo/public/cpp/bindings/map_traits.h"
@@ -63,8 +64,14 @@ bool Deserialize(DataType&& input, InputUserType* output, Args&&... args) {
       *output = absl::nullopt;
       return true;
     }
-    if (!*output)
-      output->emplace();
+    if (!*output) {
+      if constexpr (std::is_constructible_v<typename InputUserType::value_type,
+                                            ::mojo::DefaultConstruct::Tag>) {
+        output->emplace(mojo::internal::DefaultConstructTag());
+      } else {
+        output->emplace();
+      }
+    }
     return Deserialize<MojomType>(std::forward<DataType>(input),
                                   &output->value(),
                                   std::forward<Args>(args)...);

pdf/loader/url_loader_unittest.cc

@@ -579,8 +579,9 @@ TEST_F(UrlLoaderTest, DidFailWithErrorNetworkAccessDenied) {
 }
 
 TEST_F(UrlLoaderTest, DidFailWithWebSecurityViolationError) {
-  blink::WebURLError error(network::CorsErrorStatus(),
-                           blink::WebURLError::HasCopyInCache::kFalse, GURL());
+  blink::WebURLError error(
+      network::CorsErrorStatus(network::mojom::CorsError::kDisallowedByMode),
+      blink::WebURLError::HasCopyInCache::kFalse, GURL());
   ASSERT_TRUE(error.is_web_security_violation());
 
   int32_t result = DidFailWithError(error);

services/network/cors/cors_url_loader_unittest.cc

@@ -2004,7 +2004,7 @@ TEST_F(CorsURLLoaderTest, DevToolsObserverOnCorsErrorCallback) {
   EXPECT_TRUE(devtools_observer.cors_error_params());
   const network::MockDevToolsObserver::OnCorsErrorParams& params =
       *devtools_observer.cors_error_params();
-  EXPECT_EQ(mojom::CorsError::kDisallowedByMode, params.status.cors_error);
+  EXPECT_EQ(mojom::CorsError::kDisallowedByMode, params.status->cors_error);
   EXPECT_EQ(initiator_origin, params.initiator_origin);
   EXPECT_EQ(url, params.url);
 }

services/network/public/cpp/cors/cors_error_status.cc

@@ -13,7 +13,7 @@
 
 namespace network {
 
-CorsErrorStatus::CorsErrorStatus() = default;
+CorsErrorStatus::CorsErrorStatus(mojo::DefaultConstruct::Tag) {}
 
 CorsErrorStatus::CorsErrorStatus(const CorsErrorStatus&) = default;
 CorsErrorStatus& CorsErrorStatus::operator=(const CorsErrorStatus&) = default;

services/network/public/cpp/cors/cors_error_status.h

@@ -10,6 +10,7 @@
 
 #include "base/component_export.h"
 #include "base/unguessable_token.h"
+#include "mojo/public/cpp/bindings/default_construct_tag.h"
 #include "services/network/public/mojom/cors.mojom-shared.h"
 #include "services/network/public/mojom/ip_address_space.mojom-shared.h"
 
@@ -17,12 +18,6 @@ namespace network {
 
 // Type-mapped to `network::mojom::CorsErrorStatus`.
 struct COMPONENT_EXPORT(NETWORK_CPP_BASE) CorsErrorStatus {
-  // This constructor is used by generated IPC serialization code.
-  // Should not use this explicitly.
-  // TODO(toyoshim, yhirano): Exploring a way to make this private, and allows
-  // only serialization code for mojo can access.
-  CorsErrorStatus();
-
   // Instances of this type are copyable and efficiently movable.
   CorsErrorStatus(const CorsErrorStatus&);
   CorsErrorStatus& operator=(const CorsErrorStatus&);
@@ -43,6 +38,9 @@ struct COMPONENT_EXPORT(NETWORK_CPP_BASE) CorsErrorStatus {
   bool operator==(const CorsErrorStatus& rhs) const;
   bool operator!=(const CorsErrorStatus& rhs) const { return !(*this == rhs); }
 
+  // This constructor is used by generated IPC serialization code.
+  explicit CorsErrorStatus(mojo::DefaultConstruct::Tag);
+
   // NOTE: This value is meaningless and should be overridden immediately either
   // by a constructor or by Mojo deserialization code.
   mojom::CorsError cors_error = mojom::CorsError::kMaxValue;

services/network/public/cpp/cors/cors_mojom_traits_unittest.cc

@@ -13,14 +13,13 @@ namespace network {
 namespace {
 
 TEST(CorsMojomTraitsTest, CorsErrorStatusMojoRoundTrip) {
-  CorsErrorStatus original;
-  original.cors_error = mojom::CorsError::kInsecurePrivateNetwork;
+  CorsErrorStatus original(mojom::CorsError::kInsecurePrivateNetwork,
+                           mojom::IPAddressSpace::kLoopback,
+                           mojom::IPAddressSpace::kLocal);
   original.failed_parameter = "bleep";
-  original.target_address_space = mojom::IPAddressSpace::kLocal;
-  original.resource_address_space = mojom::IPAddressSpace::kLoopback;
   original.has_authorization_covered_by_wildcard_on_preflight = true;
 
-  CorsErrorStatus copy;
+  CorsErrorStatus copy(mojom::CorsError::kInvalidResponse);
   EXPECT_TRUE(mojo::test::SerializeAndDeserialize<mojom::CorsErrorStatus>(
       original, copy));
   EXPECT_EQ(original, copy);

services/network/public/mojom/BUILD.gn

@@ -664,6 +664,7 @@ mojom("url_loader_base") {
         {
           mojom = "network.mojom.CorsErrorStatus"
           cpp = "::network::CorsErrorStatus"
+          default_constructible = false
         },
       ]
       traits_headers =

services/network/test/mock_devtools_observer.h

@@ -17,6 +17,7 @@
 #include "services/network/public/mojom/http_raw_headers.mojom-forward.h"
 #include "services/network/public/mojom/ip_address_space.mojom-forward.h"
 #include "testing/gmock/include/gmock/gmock.h"
+#include "third_party/abseil-cpp/absl/types/optional.h"
 
 namespace network {
 
@@ -179,7 +180,7 @@ class MockDevToolsObserver : public mojom::DevToolsObserver {
     absl::optional<::url::Origin> initiator_origin;
     mojom::ClientSecurityStatePtr client_security_state;
     GURL url;
-    network::CorsErrorStatus status;
+    absl::optional<network::CorsErrorStatus> status;
     bool is_warning = false;
   };