Adding checks for V8 functions returning Maybe<bool>

third_party/WebKit/Source/bindings/core/v8/custom/V8WindowCustom.cpp

Index: third_party/WebKit/Source/bindings/core/v8/custom/V8WindowCustom.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/custom/V8WindowCustom.cpp b/third_party/WebKit/Source/bindings/core/v8/custom/V8WindowCustom.cpp
index 730dd279d54f78797565f1c0ed8ca18ecb84ec9e..a657595a6109f74e1f1b7b84a6437963ae175d75 100644
--- a/third_party/WebKit/Source/bindings/core/v8/custom/V8WindowCustom.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/custom/V8WindowCustom.cpp
@@ -144,7 +144,9 @@ void V8Window::openerAttributeSetterCustom(v8::Local<v8::Value> value, const v8:
     }
 
     // Delete the accessor from the inner object.
-    info.Holder()->Delete(isolate->GetCurrentContext(), v8AtomicString(isolate, "opener"));
+    if (info.Holder()->Delete(isolate->GetCurrentContext(), v8AtomicString(isolate, "opener")).IsNothing()) {
+        return;
+    }
 
     // Put property on the inner object.
     if (info.Holder()->IsObject()) {