[inspector] Add internal property to identify detached ArrayBuffers.

This adds an internal property [[IsDetached]] to the inspector preview
of ArrayBuffer instances, which indicates whether the ArrayBuffer was
detached (i.e. transfered via `postMessage`). Previously it was rather
impossible to tell whether an ArrayBuffer was detached, you had to know
that V8 violates the ECMAScript specification and simply sets the
byteLength accessor to 0 upon detaching an ArrayBuffer (but even then it
was still impossible to tell whether that ArrayBuffer wasn't simply an
empty one from the get go).

Before: https://imgur.com/UcOF83c
After: https://imgur.com/WjmTehZ

Fixed: chromium:1109102
Change-Id: I8fb6e2be2fbfe5c62b05dc9d2a0f18378eb4de6c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2316075
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Auto-Submit: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69034}

src/runtime/runtime-debug.cc

@@ -304,6 +304,15 @@ MaybeHandle<JSArray> Runtime::GetInternalProperties(Isolate* isolate,
     result->set(0, *primitive_value);
     result->set(1, js_value->value());
     return factory->NewJSArrayWithElements(result);
+  } else if (object->IsJSArrayBuffer()) {
+    Handle<JSArrayBuffer> js_array_buffer = Handle<JSArrayBuffer>::cast(object);
+    Handle<FixedArray> result = factory->NewFixedArray(1 * 2);
+
+    Handle<String> is_detached_str =
+        factory->NewStringFromAsciiChecked("[[IsDetached]]");
+    result->set(0, *is_detached_str);
+    result->set(1, isolate->heap()->ToBoolean(js_array_buffer->was_detached()));
+    return factory->NewJSArrayWithElements(result);
   }
   return factory->NewJSArray(0);
 }

test/inspector/debugger/get-properties-paused-expected.txt

@@ -87,3 +87,5 @@ Running test: testArrayBufferWithBrokenUintCtor
   [[Int8Array]] own object undefined
   [[Uint8Array]] own object undefined
   __proto__ own object undefined
+Internal properties
+  [[IsDetached]] boolean false

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

@@ -102,6 +102,7 @@ Running test: testArrayBuffer
   0 own number 16843009
   1 own number 16843009
   __proto__ own object undefined
+[[IsDetached]] false
 
 Running test: testDetachedArrayBuffer
 [[Int8Array]]
@@ -112,8 +113,11 @@ Running test: testDetachedArrayBuffer
   __proto__ own object undefined
 [[Int32Array]]
   __proto__ own object undefined
+[[IsDetached]] true
 
 Running test: testArrayBufferWithBrokenUintCtor
   [[Int8Array]] own object undefined
   [[Uint8Array]] own object undefined
   __proto__ own object undefined
+Internal properties
+  [[IsDetached]] boolean false

test/inspector/runtime/get-properties.js

@@ -50,6 +50,9 @@ InspectorTest.runAsyncTestSuite([
       InspectorTest.log(prop.name);
       await logGetPropertiesResult(prop.value.objectId);
     }
+    for (let prop of props.result.internalProperties) {
+      InspectorTest.log(prop.name + ' ' + prop.value.value);
+    }
   },
 
   async function testDetachedArrayBuffer() {
@@ -65,6 +68,9 @@ InspectorTest.runAsyncTestSuite([
       InspectorTest.log(prop.name);
       await logGetPropertiesResult(prop.value.objectId);
     }
+    for (let prop of props.result.internalProperties) {
+      InspectorTest.log(prop.name + ' ' + prop.value.value);
+    }
   },
 
   async function testArrayBufferWithBrokenUintCtor() {