Make base::Value::TYPE a scoped enum.

ios/web/web_state/ui/web_view_js_utils.mm

Index: ios/web/web_state/ui/web_view_js_utils.mm
diff --git a/ios/web/web_state/ui/web_view_js_utils.mm b/ios/web/web_state/ui/web_view_js_utils.mm
index 5036d489eb371de273863e7c89db989c77bab6ca..fb402fdd812e5c55e1e769d994c31b57722a604a 100644
--- a/ios/web/web_state/ui/web_view_js_utils.mm
+++ b/ios/web/web_state/ui/web_view_js_utils.mm
@@ -33,17 +33,17 @@ std::unique_ptr<base::Value> ValueResultFromWKResult(id wk_result,
   CFTypeID result_type = CFGetTypeID(wk_result);
   if (result_type == CFStringGetTypeID()) {
     result.reset(new base::StringValue(base::SysNSStringToUTF16(wk_result)));
-    DCHECK(result->IsType(base::Value::TYPE_STRING));
+    DCHECK(result->IsType(base::Value::Type::STRING));
   } else if (result_type == CFNumberGetTypeID()) {
     result.reset(new base::FundamentalValue([wk_result doubleValue]));
-    DCHECK(result->IsType(base::Value::TYPE_DOUBLE));
+    DCHECK(result->IsType(base::Value::Type::DOUBLE));
   } else if (result_type == CFBooleanGetTypeID()) {
     result.reset(
         new base::FundamentalValue(static_cast<bool>([wk_result boolValue])));
-    DCHECK(result->IsType(base::Value::TYPE_BOOLEAN));
+    DCHECK(result->IsType(base::Value::Type::BOOLEAN));
   } else if (result_type == CFNullGetTypeID()) {
     result = base::Value::CreateNullValue();
-    DCHECK(result->IsType(base::Value::TYPE_NULL));
+    DCHECK(result->IsType(base::Value::Type::NONE));
   } else if (result_type == CFDictionaryGetTypeID()) {
     std::unique_ptr<base::DictionaryValue> dictionary =
         base::MakeUnique<base::DictionaryValue>();