Reland and fix "Allow ICs to be generated for own global proxy."

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 2db83f2ba0225a4910bbb340d3b6bb436e7068a1..4c49170182a3888f7ef07ef8e456f28ca09754a0 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -927,7 +927,8 @@ bool Object::IsJSGlobalProxy() {
   bool result = IsHeapObject() &&
                 (HeapObject::cast(this)->map()->instance_type() ==
                  JS_GLOBAL_PROXY_TYPE);
-  ASSERT(!result || IsAccessCheckNeeded());
+  ASSERT(!result ||
+         HeapObject::cast(this)->map()->is_access_check_needed());
   return result;
 }
 
@@ -952,8 +953,14 @@ bool Object::IsUndetectableObject() {
 
 
 bool Object::IsAccessCheckNeeded() {
-  return IsHeapObject()
-    && HeapObject::cast(this)->map()->is_access_check_needed();
+  if (!IsHeapObject()) return false;
+  if (IsJSGlobalProxy()) {
+    JSGlobalProxy* proxy = JSGlobalProxy::cast(this);
+    GlobalObject* global =
+        proxy->GetIsolate()->context()->global_object();
+    return proxy->IsDetachedFrom(global);
+  }
+  return HeapObject::cast(this)->map()->is_access_check_needed();
 }