Prevent an upcoming circular dependency between native_value_traits_impl.h and script_promise.h

In a future CL (https://chromium-review.googlesource.com/c/chromium/src/+/5908900),
we will add logic to script_promise.h that requires including
native_value_traits_impl.h. But native_value_traits_impl.h already
includes script_promise.h, so that would be a circular dependency.

To resolve this:
* Move NativeValueTraits<IDLPromise<T>> to script_promise.h, so
  that native_value_traits_impl.h no longer needs to include
  script_promise.h, and add the native_value_traits_impl.h include
  to script_promise.h
* This creates another circular dependency:
  native_value_traits_impl.h -> script_iterator.h ->
  script_promise.h -> native_value_traits_impl.h
  Remove this circular dependency by having script_iterator.h
  use forward-declares for ScriptPromise
* to_v8_traits.h was depending on a transitive include of
  script_promise.h that is no longer there. Include it directly.

Change-Id: I507ecedce417309aaaf76f20c3f6684012708537
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5915794
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Commit-Queue: Nate Chapin <japhet@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1367805}

Author: natechapin

third_party/blink/renderer/bindings/core/v8/native_value_traits_impl.h

@@ -13,7 +13,6 @@
 #include "third_party/blink/renderer/bindings/core/v8/native_value_traits.h"
 #include "third_party/blink/renderer/bindings/core/v8/pass_as_span.h"
 #include "third_party/blink/renderer/bindings/core/v8/script_iterator.h"
-#include "third_party/blink/renderer/bindings/core/v8/script_promise.h"
 #include "third_party/blink/renderer/bindings/core/v8/script_value.h"
 #include "third_party/blink/renderer/bindings/core/v8/v8_binding_for_core.h"
 #include "third_party/blink/renderer/bindings/core/v8/v8_trusted_html.h"
@@ -916,17 +915,6 @@ struct CORE_EXPORT NativeValueTraits<IDLNullable<IDLObject>>
   }
 };
 
-// Promise types
-template <typename T>
-struct NativeValueTraits<IDLPromise<T>>
-    : public NativeValueTraitsBase<IDLPromise<T>> {
-  static ScriptPromise<T> NativeValue(v8::Isolate* isolate,
-                                      v8::Local<v8::Value> value,
-                                      ExceptionState&) {
-    return ScriptPromise<T>::FromV8Value(isolate, value);
-  }
-};
-
 // IDLNullable<IDLPromise> must not be used.
 template <typename T>
 struct NativeValueTraits<IDLNullable<IDLPromise<T>>>;

third_party/blink/renderer/bindings/core/v8/script_iterator.h

@@ -6,7 +6,7 @@
 #define THIRD_PARTY_BLINK_RENDERER_BINDINGS_CORE_V8_SCRIPT_ITERATOR_H_
 
 #include "third_party/abseil-cpp/absl/types/variant.h"
-#include "third_party/blink/renderer/bindings/core/v8/script_promise.h"
+#include "third_party/blink/renderer/bindings/core/v8/idl_types.h"
 #include "third_party/blink/renderer/bindings/core/v8/world_safe_v8_reference.h"
 #include "third_party/blink/renderer/core/core_export.h"
 #include "third_party/blink/renderer/platform/heap/garbage_collected.h"
@@ -15,8 +15,12 @@
 
 namespace blink {
 
+class ExceptionContext;
 class ExceptionState;
 class ExecutionContext;
+class ScriptPromiseUntyped;
+template <typename IDLResolvedType>
+class ScriptPromise;
 
 // This class provides a wrapper for iterating over any ES object that
 // implements either the async iterable and async iterator protocols, or the

third_party/blink/renderer/bindings/core/v8/script_promise.h

@@ -34,6 +34,7 @@
 #include "base/memory/scoped_refptr.h"
 #include "base/memory/stack_allocated.h"
 #include "third_party/blink/renderer/bindings/core/v8/idl_types.h"
+#include "third_party/blink/renderer/bindings/core/v8/native_value_traits_impl.h"
 #include "third_party/blink/renderer/bindings/core/v8/script_value.h"
 #include "third_party/blink/renderer/bindings/core/v8/v8_binding_for_core.h"
 #include "third_party/blink/renderer/core/core_export.h"
@@ -53,6 +54,18 @@ class ScriptFunction;
 template <typename IDLResolvedType>
 class ScriptPromise;
 
+// Defined here rather than in native_value_traits_impl.h to avoid a circular
+// dependency.
+template <typename T>
+struct NativeValueTraits<IDLPromise<T>>
+    : public NativeValueTraitsBase<IDLPromise<T>> {
+  static ScriptPromise<T> NativeValue(v8::Isolate* isolate,
+                                      v8::Local<v8::Value> value,
+                                      ExceptionState&) {
+    return ScriptPromise<T>::FromV8Value(isolate, std::move(value));
+  }
+};
+
 // ScriptPromise is the class for representing Promise values in C++
 // world. ScriptPromise holds a Promise. Holding a `ScriptPromise`
 // is rarely needed — typically you hold a `ScriptPromiseResolver` when creating

third_party/blink/renderer/bindings/core/v8/to_v8_traits.h

@@ -15,6 +15,7 @@
 #include "base/numerics/safe_conversions.h"
 #include "third_party/blink/renderer/bindings/core/v8/idl_types.h"
 #include "third_party/blink/renderer/bindings/core/v8/native_value_traits_impl.h"
+#include "third_party/blink/renderer/bindings/core/v8/script_promise.h"
 #include "third_party/blink/renderer/platform/bindings/dom_data_store.h"
 #include "third_party/blink/renderer/platform/bindings/v8_binding.h"
 #include "third_party/blink/renderer/platform/heap/collection_support/heap_deque.h"