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 263c8dd490556c318cd40f4dc2045b4e0108563d..3eeb16655428b4fd52d2a6b07f05dba8e1fb189a 100644
--- a/third_party/WebKit/Source/bindings/core/v8/custom/V8WindowCustom.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/custom/V8WindowCustom.cpp
@@ -214,8 +214,10 @@ void V8Window::openerAttributeSetterCustom(
   }
 
   // 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()) {