[proxies] Implement [[Delete]].

test/cctest/test-elements-kind.cc

 // Copyright 2015 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.
 
 // TODO(jochen): Remove this after the setting is turned on globally.
 #define V8_IMMINENT_DEPRECATION_WARNINGS
 
 #include <stdlib.h>
 #include <utility>
 
@@ skipping 296 matching lines @@
   JSObject::DefinePropertyOrElementIgnoreAttributes(array, name, value_smi,
                                                     NONE)
       .Check();
   // no change in elements_kind => no map transition
   CHECK_EQ(array->map(), *previous_map);
   CHECK_EQ(array->map()->elements_kind(), FAST_SMI_ELEMENTS);
   CHECK_EQ(1, Smi::cast(array->length())->value());
 
   // `delete array[0]` does not alter length, but changes the elments_kind
   name = MakeString("0");
-  JSReceiver::DeletePropertyOrElement(array, name).Check();
+  CHECK(JSReceiver::DeletePropertyOrElement(array, name).FromMaybe(false));
   CHECK_NE(array->map(), *previous_map);
   CHECK_EQ(array->map()->elements_kind(), FAST_HOLEY_SMI_ELEMENTS);
   CHECK_EQ(1, Smi::cast(array->length())->value());
   previous_map = handle(array->map());
 
   // add a couple of elements again
   name = MakeString("0");
   JSObject::DefinePropertyOrElementIgnoreAttributes(array, name, value_smi,
                                                     NONE)
       .Check();
@@ skipping 52 matching lines @@
   JSObject::DefinePropertyOrElementIgnoreAttributes(array, name, value_smi,
                                                     NONE)
       .Check();
   // no change in elements_kind => no map transition
   CHECK_EQ(array->map(), *previous_map);
   CHECK_EQ(array->map()->elements_kind(), FAST_ELEMENTS);
   CHECK_EQ(1, Smi::cast(array->length())->value());
 
   // `delete array[0]` does not alter length, but changes the elments_kind
   name = MakeString("0");
-  JSReceiver::DeletePropertyOrElement(array, name).Check();
+  CHECK(JSReceiver::DeletePropertyOrElement(array, name).FromMaybe(false));
   CHECK_NE(array->map(), *previous_map);
   CHECK_EQ(array->map()->elements_kind(), FAST_HOLEY_ELEMENTS);
   CHECK_EQ(1, Smi::cast(array->length())->value());
   previous_map = handle(array->map());
 
   // add a couple of elements, elements_kind stays HOLEY
   name = MakeString("0");
   JSObject::DefinePropertyOrElementIgnoreAttributes(array, name, value_string,
                                                     NONE)
       .Check();
@@ skipping 36 matching lines @@
   name = MakeString("1");
   JSObject::DefinePropertyOrElementIgnoreAttributes(array, name, value_smi,
                                                     NONE)
       .Check();
   CHECK_EQ(array->map(), *previous_map);
   CHECK_EQ(array->map()->elements_kind(), FAST_DOUBLE_ELEMENTS);
   CHECK_EQ(2, Smi::cast(array->length())->value());
 
   // `delete array[0]` does not alter length, but changes the elments_kind
   name = MakeString("0");
-  JSReceiver::DeletePropertyOrElement(array, name).Check();
+  CHECK(JSReceiver::DeletePropertyOrElement(array, name).FromMaybe(false));
   CHECK_NE(array->map(), *previous_map);
   CHECK_EQ(array->map()->elements_kind(), FAST_HOLEY_DOUBLE_ELEMENTS);
   CHECK_EQ(2, Smi::cast(array->length())->value());
   previous_map = handle(array->map());
 
   // filling the hole `array[0] = value_smi` again doesn't transition back
   name = MakeString("0");
   JSObject::DefinePropertyOrElementIgnoreAttributes(array, name, value_double,
                                                     NONE)
       .Check();
@@ skipping 11 matching lines @@
   CHECK_EQ(2, Smi::cast(array->length())->value());
   previous_map = handle(array->map());
 
   // Adding a double doesn't change the map
   name = MakeString("0");
   JSObject::DefinePropertyOrElementIgnoreAttributes(array, name, value_double,
                                                     NONE)
       .Check();
   CHECK_EQ(array->map(), *previous_map);
 }