Use new downcast helper for blink::IDBCursorWithValue

This CL has two goals,
  1. Use To<IDBCursorWithValue> and DynamicTo<IDBCursorWithValue> as new
   downcast helper
  2. Use IsA<IDBCursorWithValue>(element) in place of
   IsIDBCursorWithValue(element)

Bug: 891908
Change-Id: I495cfb89dabb4242f86fcbe62cf295afcf1eda10
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2019646Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Abhijeet Kandalkar <abhijeet@igalia.com>
Cr-Commit-Position: refs/heads/master@{#744589}

third_party/blink/renderer/modules/indexeddb/idb_any.cc

@@ -59,8 +59,8 @@ IDBCursor* IDBAny::IdbCursor() const {
 
 IDBCursorWithValue* IDBAny::IdbCursorWithValue() const {
   DCHECK_EQ(type_, kIDBCursorWithValueType);
-  SECURITY_DCHECK(idb_cursor_->IsCursorWithValue());
-  return ToIDBCursorWithValue(idb_cursor_.Get());
+  SECURITY_DCHECK(IsA<IDBCursorWithValue>(idb_cursor_.Get()));
+  return To<IDBCursorWithValue>(idb_cursor_.Get());
 }
 
 IDBDatabase* IDBAny::IdbDatabase() const {
@@ -93,8 +93,8 @@ IDBAny::IDBAny(DOMStringList* value)
     : type_(kDOMStringListType), dom_string_list_(value) {}
 
 IDBAny::IDBAny(IDBCursor* value)
-    : type_(value->IsCursorWithValue() ? kIDBCursorWithValueType
-                                       : kIDBCursorType),
+    : type_(IsA<IDBCursorWithValue>(value) ? kIDBCursorWithValueType
+                                           : kIDBCursorType),
       idb_cursor_(value) {}
 
 IDBAny::IDBAny(IDBDatabase* value)

third_party/blink/renderer/modules/indexeddb/idb_cursor.cc

@@ -32,6 +32,7 @@
 #include "third_party/blink/renderer/bindings/modules/v8/v8_idb_request.h"
 #include "third_party/blink/renderer/modules/indexed_db_names.h"
 #include "third_party/blink/renderer/modules/indexeddb/idb_any.h"
+#include "third_party/blink/renderer/modules/indexeddb/idb_cursor_with_value.h"
 #include "third_party/blink/renderer/modules/indexeddb/idb_database.h"
 #include "third_party/blink/renderer/modules/indexeddb/idb_object_store.h"
 #include "third_party/blink/renderer/modules/indexeddb/idb_tracing.h"
@@ -41,6 +42,7 @@
 #include "third_party/blink/renderer/platform/bindings/script_state.h"
 #include "third_party/blink/renderer/platform/bindings/v8_private_property.h"
 #include "third_party/blink/renderer/platform/heap/heap.h"
+#include "third_party/blink/renderer/platform/wtf/casting.h"
 
 namespace blink {
 
@@ -392,7 +394,7 @@ ScriptValue IDBCursor::primaryKey(ScriptState* script_state) {
 }
 
 ScriptValue IDBCursor::value(ScriptState* script_state) {
-  DCHECK(IsCursorWithValue());
+  DCHECK(IsA<IDBCursorWithValue>(this));
 
   IDBAny* value;
   if (value_) {
@@ -430,7 +432,7 @@ void IDBCursor::SetValueReady(std::unique_ptr<IDBKey> key,
 
   got_value_ = true;
 
-  if (!IsCursorWithValue())
+  if (!IsA<IDBCursorWithValue>(this))
     return;
 
   value_dirty_ = true;

third_party/blink/renderer/modules/indexeddb/idb_cursor_with_value.h

@@ -31,6 +31,7 @@
 #include "third_party/blink/renderer/modules/indexeddb/idb_cursor.h"
 #include "third_party/blink/renderer/modules/indexeddb/indexed_db.h"
 #include "third_party/blink/renderer/modules/indexeddb/web_idb_cursor.h"
+#include "third_party/blink/renderer/platform/wtf/casting.h"
 
 namespace blink {
 
@@ -56,11 +57,12 @@ class IDBCursorWithValue final : public IDBCursor {
   bool IsCursorWithValue() const override { return true; }
 };
 
-DEFINE_TYPE_CASTS(IDBCursorWithValue,
-                  IDBCursor,
-                  cursor,
-                  cursor->IsCursorWithValue(),
-                  cursor.IsCursorWithValue());
+template <>
+struct DowncastTraits<IDBCursorWithValue> {
+  static bool AllowFrom(const IDBCursor& cursor) {
+    return cursor.IsCursorWithValue();
+  }
+};
 
 }  // namespace blink