[regexp] Simplify GetCapture

src/runtime/runtime-regexp.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/conversions-inl.h"
 #include "src/isolate-inl.h"
 #include "src/messages.h"
@@ skipping 883 matching lines @@
                        Handle<JSObject> match_info)
       : isolate_(isolate), match_info_(match_info) {
     subject_ = String::Flatten(subject);
   }
 
   Handle<String> GetMatch() override {
     return RegExpUtils::GenericCaptureGetter(isolate_, match_info_, 0, nullptr);
   }
 
   MaybeHandle<String> GetCapture(int i, bool* capture_exists) override {
-    Handle<Object> capture_obj =
-        RegExpUtils::GenericCaptureGetter(isolate_, match_info_, i);
-    if (capture_obj->IsUndefined(isolate_)) {
-      *capture_exists = false;
-      return isolate_->factory()->empty_string();
-    }
-    *capture_exists = true;
-    return Object::ToString(isolate_, capture_obj);
+    Handle<Object> capture_obj = RegExpUtils::GenericCaptureGetter(
+        isolate_, match_info_, i, capture_exists);
+    return (*capture_exists) ? Object::ToString(isolate_, capture_obj)
+                             : isolate_->factory()->empty_string();
   }
 
   Handle<String> GetPrefix() override {
     const int match_start =
         RegExpUtils::GetLastMatchCapture(isolate_, match_info_, 0);
     return isolate_->factory()->NewSubString(subject_, 0, match_start);
   }
 
   Handle<String> GetSuffix() override {
     const int match_end =
@@ skipping 753 matching lines @@
 
 RUNTIME_FUNCTION(Runtime_IsRegExp) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_CHECKED(Object, obj, 0);
   return isolate->heap()->ToBoolean(obj->IsJSRegExp());
 }
 
 }  // namespace internal
 }  // namespace v8