[inspector] Don't pretend that native accessors are own properties.

Previously the V8 inspector would report native accessors, whose getter
evaluates to a value without causing a side effect, as own data
properties. But then the DevTools front-end will not be able to tell
whether that accessor was actually an own property or just an inherited
accessor.

The reason for reporting them as own properties in the first place was
to ensure that these properties show up in the object's preview. But
that we can handle differently by just marking these properties as
synthetic internally and including them in the preview.

Bug: chromium:1076820
Change-Id: I223299af7954e7b1a4a16bb5180d4ceff50f170f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3094005
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Kim-Anh Tran <kimanh@chromium.org>
Auto-Submit: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Kim-Anh Tran <kimanh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76276}

src/inspector/value-mirror.cc

@@ -786,7 +786,7 @@ class PreviewPropertyAccumulator : public ValueMirror::PropertyAccumulator {
         !mirror.value) {
       return true;
     }
-    if (!mirror.isOwn) return true;
+    if (!mirror.isOwn && !mirror.isSynthetic) return true;
     if (std::find(m_blocklist.begin(), m_blocklist.end(), mirror.name) !=
         m_blocklist.end()) {
       return true;
@@ -1288,7 +1288,6 @@ bool ValueMirror::getProperties(v8::Local<v8::Context> context,
                                           nullptr, true)
                     .ToLocal(&value)) {
               valueMirror = ValueMirror::create(context, value);
-              isOwn = true;
               setterMirror = nullptr;
               getterMirror = nullptr;
             }
@@ -1303,6 +1302,7 @@ bool ValueMirror::getProperties(v8::Local<v8::Context> context,
                                  enumerable,
                                  isOwn,
                                  iterator->is_array_index(),
+                                 isAccessorProperty && valueMirror,
                                  std::move(valueMirror),
                                  std::move(getterMirror),
                                  std::move(setterMirror),

src/inspector/value-mirror.h

@@ -38,6 +38,7 @@ struct PropertyMirror {
   bool enumerable;
   bool isOwn;
   bool isIndex;
+  bool isSynthetic;
   std::unique_ptr<ValueMirror> value;
   std::unique_ptr<ValueMirror> getter;
   std::unique_ptr<ValueMirror> setter;

test/inspector/runtime/get-properties-expected.txt

@@ -26,6 +26,34 @@ Running test: testNotOwn
 Internal properties
   [[Prototype]] object undefined
 
+Running test: testNotOwnSet
+  Symbol(Symbol.iterator) inherited function undefined
+  Symbol(Symbol.toStringTag) inherited string Set
+  __defineGetter__ inherited function undefined
+  __defineSetter__ inherited function undefined
+  __lookupGetter__ inherited function undefined
+  __lookupSetter__ inherited function undefined
+  __proto__ inherited no value, getter, setter
+  add inherited function undefined
+  clear inherited function undefined
+  constructor inherited function undefined
+  delete inherited function undefined
+  entries inherited function undefined
+  forEach inherited function undefined
+  has inherited function undefined
+  hasOwnProperty inherited function undefined
+  isPrototypeOf inherited function undefined
+  keys inherited function undefined
+  propertyIsEnumerable inherited function undefined
+  size inherited number 3
+  toLocaleString inherited function undefined
+  toString inherited function undefined
+  valueOf inherited function undefined
+  values inherited function undefined
+Internal properties
+  [[Entries]] object undefined
+  [[Prototype]] object undefined
+
 Running test: testAccessorsOnly
   b own no value, getter, setter
   d own no value, setter

test/inspector/runtime/get-properties.js

@@ -15,6 +15,10 @@ InspectorTest.runAsyncTestSuite([
     return logExpressionProperties('({ a: 2, set b(_) {}, get b() {return 5;}, __proto__: { a: 3, c: 4, get d() {return 6;} }})', { ownProperties: false });
   },
 
+  function testNotOwnSet() {
+    return logExpressionProperties('new Set([1, 2, 3])', { ownProperties: false });
+  },
+
   function testAccessorsOnly() {
     return logExpressionProperties('({ a: 2, set b(_) {}, get b() {return 5;}, c: \'c\', set d(_){} })', { ownProperties: true, accessorPropertiesOnly: true});
   },