Partial Reland [base] Make HasTrait() use types instead of args

Partial reland of https://chromium-review.googlesource.com/c/chromium/src/+/1635827

Extracted HasTraits() modification to make revertable part of the
desired change as small as possible.

TBR=fdoray@chromium.org

Bug: 968047
Change-Id: I9683326cceee53164e4482d71cf6929296a8db7a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1762332
Commit-Queue: Gabriel Charette <gab@chromium.org>
Reviewed-by: François Doray <fdoray@chromium.org>
Cr-Commit-Position: refs/heads/master@{#688682}

base/task/task_traits.h

@@ -231,14 +231,15 @@ class BASE_EXPORT TaskTraits {
             static_cast<uint8_t>(
                 trait_helpers::GetEnum<TaskPriority,
                                        TaskPriority::USER_BLOCKING>(args...)) |
-            (trait_helpers::HasTrait<TaskPriority>(args...) ? kIsExplicitFlag
-                                                            : 0)),
+            (trait_helpers::HasTrait<TaskPriority, ArgTypes...>()
+                 ? kIsExplicitFlag
+                 : 0)),
         shutdown_behavior_(
             static_cast<uint8_t>(
                 trait_helpers::GetEnum<TaskShutdownBehavior,
                                        TaskShutdownBehavior::SKIP_ON_SHUTDOWN>(
                     args...)) |
-            (trait_helpers::HasTrait<TaskShutdownBehavior>(args...)
+            (trait_helpers::HasTrait<TaskShutdownBehavior, ArgTypes...>()
                  ? kIsExplicitFlag
                  : 0)),
         thread_policy_(
@@ -246,12 +247,13 @@ class BASE_EXPORT TaskTraits {
                 trait_helpers::GetEnum<ThreadPolicy,
                                        ThreadPolicy::PREFER_BACKGROUND>(
                     args...)) |
-            (trait_helpers::HasTrait<ThreadPolicy>(args...) ? kIsExplicitFlag
-                                                            : 0)),
-        may_block_(trait_helpers::HasTrait<MayBlock>(args...)),
+            (trait_helpers::HasTrait<ThreadPolicy, ArgTypes...>()
+                 ? kIsExplicitFlag
+                 : 0)),
+        may_block_(trait_helpers::HasTrait<MayBlock, ArgTypes...>()),
         with_base_sync_primitives_(
-            trait_helpers::HasTrait<WithBaseSyncPrimitives>(args...)),
-        use_thread_pool_(trait_helpers::HasTrait<ThreadPool>(args...)) {}
+            trait_helpers::HasTrait<WithBaseSyncPrimitives, ArgTypes...>()),
+        use_thread_pool_(trait_helpers::HasTrait<ThreadPool, ArgTypes...>()) {}
 
   constexpr TaskTraits(const TaskTraits& other) = default;
   TaskTraits& operator=(const TaskTraits& other) = default;

base/task/test_task_traits_extension.h

@@ -34,7 +34,8 @@ class TestTaskTraitsExtension {
       : enum_trait_(
             trait_helpers::GetEnum<TestExtensionEnumTrait,
                                    TestExtensionEnumTrait::kA>(args...)),
-        bool_trait_(trait_helpers::HasTrait<TestExtensionBoolTrait>(args...)) {}
+        bool_trait_(
+            trait_helpers::HasTrait<TestExtensionBoolTrait, ArgTypes...>()) {}
 
   constexpr TaskTraitsExtensionStorage Serialize() const {
     return {kExtensionId, {{static_cast<uint8_t>(enum_trait_), bool_trait_}}};

base/test/scoped_task_environment.h

@@ -174,7 +174,8 @@ class TaskEnvironment {
                                    ThreadPoolExecutionMode::DEFAULT>(args...),
             trait_helpers::GetEnum<ThreadingMode, ThreadingMode::DEFAULT>(
                 args...),
-            trait_helpers::HasTrait<SubclassCreatesDefaultTaskRunner>(args...),
+            trait_helpers::HasTrait<SubclassCreatesDefaultTaskRunner,
+                                    ArgTypes...>(),
             trait_helpers::NotATraitTag()) {}
 
   // Waits until no undelayed ThreadPool tasks remain. Then, unregisters the

base/traits_bag.h

@@ -47,7 +47,8 @@
 //                 trait_helpers::AreValidTraits<ValidTraits,
 //                                               ArgTypes...>::value>>
 //   constexpr void DoSomethingAwesome(ArgTypes... args)
-//      : enable_feature_x(trait_helpers::HasTrait<EnableFeatureX>(args...)),
+//      : enable_feature_x(
+//            trait_helpers::HasTrait<EnableFeatureX, ArgTypes...>()),
 //        color(trait_helpers::GetEnum<Color, EnumTraitA::BLUE>(args...)) {}
 
 namespace base {
@@ -246,7 +247,7 @@ static constexpr Optional<Enum> GetOptionalEnum(Args... args) {
 
 // Helper to make checking for the presence of a trait more readable.
 template <typename Trait, typename... Args>
-static constexpr bool HasTrait(Args... args) {
+static constexpr bool HasTrait() {
   static_assert(
       count({std::is_constructible<Trait, Args>::value...}, true) <= 1,
       "The traits bag contains multiple traits of the same type.");

base/traits_bag_unittest.cc

@@ -30,7 +30,7 @@ struct TestTraits {
             class CheckArgumentsAreValid = std::enable_if_t<
                 trait_helpers::AreValidTraits<ValidTrait, ArgTypes...>::value>>
   constexpr TestTraits(ArgTypes... args)
-      : has_example_trait(trait_helpers::HasTrait<ExampleTrait>(args...)),
+      : has_example_trait(trait_helpers::HasTrait<ExampleTrait, ArgTypes...>()),
         enum_trait_a(
             trait_helpers::GetEnum<EnumTraitA, EnumTraitA::A>(args...)),
         enum_trait_b(

base/traits_bag_unittest.nc

@@ -31,7 +31,7 @@ struct TestTraits {
                 trait_helpers::AreValidTraits<ValidTrait, ArgTypes...>::value>>
   constexpr TestTraits(ArgTypes... args)
       : required_trait(trait_helpers::GetEnum<RequiredTrait>(args...)),
-        boolean_trait(trait_helpers::HasTrait<BooleanTrait>(args...)) {}
+        boolean_trait(trait_helpers::HasTrait<BooleanTrait, ArgTypes...>()) {}
 
   const RequiredTrait required_trait;
   const bool boolean_trait;

chrome/test/base/browser_with_test_window_test.h

@@ -98,7 +98,7 @@ class BrowserWithTestWindowTest : public testing::Test {
                     args)...),
             base::trait_helpers::GetEnum<Browser::Type, Browser::TYPE_NORMAL>(
                 args...),
-            base::trait_helpers::HasTrait<HostedApp>(args...)) {}
+            base::trait_helpers::HasTrait<HostedApp, ArgTypes...>()) {}
 
   ~BrowserWithTestWindowTest() override;
 

content/public/browser/browser_task_traits.h

@@ -84,7 +84,7 @@ class CONTENT_EXPORT BrowserTaskTraitsExtension {
         task_type_(
             base::trait_helpers::GetEnum<BrowserTaskType,
                                          BrowserTaskType::kDefault>(args...)),
-        nestable_(!base::trait_helpers::HasTrait<NonNestable>(args...)) {}
+        nestable_(!base::trait_helpers::HasTrait<NonNestable, ArgTypes...>()) {}
 
   // Keep in sync with UiThreadTaskTraits.java
   constexpr base::TaskTraitsExtensionStorage Serialize() const {

ios/web/public/thread/web_task_traits.h

@@ -57,7 +57,7 @@ class WebTaskTraitsExtension {
           base::trait_helpers::AreValidTraits<ValidTrait, ArgTypes...>::value>>
   constexpr WebTaskTraitsExtension(ArgTypes... args)
       : web_thread_(base::trait_helpers::GetEnum<WebThread::ID>(args...)),
-        nestable_(!base::trait_helpers::HasTrait<NonNestable>(args...)) {}
+        nestable_(!base::trait_helpers::HasTrait<NonNestable, ArgTypes...>()) {}
 
   constexpr base::TaskTraitsExtensionStorage Serialize() const {
     static_assert(8 == sizeof(WebTaskTraitsExtension),

third_party/blink/renderer/platform/scheduler/public/scheduling_policy.h

@@ -36,11 +36,11 @@ struct PLATFORM_EXPORT SchedulingPolicy {
                                                     ArgTypes...>::value>>
   constexpr SchedulingPolicy(ArgTypes... args)
       : disable_aggressive_throttling(
-            base::trait_helpers::HasTrait<DisableAggressiveThrottling>(
-                args...)),
+            base::trait_helpers::HasTrait<DisableAggressiveThrottling,
+                                          ArgTypes...>()),
         disable_back_forward_cache(
-            base::trait_helpers::HasTrait<RecordMetricsForBackForwardCache>(
-                args...)) {}
+            base::trait_helpers::HasTrait<RecordMetricsForBackForwardCache,
+                                          ArgTypes...>()) {}
 
   SchedulingPolicy() {}