Return MaybeHandle from SetElement and DeleteElement.

src/liveedit.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 190 matching lines @@
   Handle<JSArray> GetJSArray() {
     return array_;
   }
 
   Isolate* isolate() const {
     return array_->GetIsolate();
   }
 
  protected:
   void SetField(int field_position, Handle<Object> value) {
-    Handle<Object> no_failure =
-        JSObject::SetElement(array_, field_position, value, NONE, SLOPPY);
-    ASSERT(!no_failure.is_null());
-    USE(no_failure);
+    JSObject::SetElement(array_, field_position, value, NONE, SLOPPY).Assert();
   }
 
   void SetSmiValueField(int field_position, int value) {
     SetField(field_position, Handle<Smi>(Smi::FromInt(value), isolate()));
   }
 
   Handle<Object> GetField(int field_position) {
     return Object::GetElementNoExceptionThrown(
         isolate(), array_, field_position);
   }
@@ skipping 99 matching lines @@
 
   friend class JSArrayBasedStruct<SharedInfoWrapper>;
 };
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 
 } }  // namespace v8::internal
 
 #endif /* V*_LIVEEDIT_H_ */