Change {this} check for arrow functions in DebugStackTraceIterator

An upcoming CL will remove the COLLECT_NON_LOCALS support of the
ScopeIterator. The DebugStackTraceIterator uses the list of non-locals
to restore the receiver for arrow functions.

This CL extracts the relevant logic into a small helper and calls
it directly.

Change-Id: Ia396fd599e41ca65810497d2f5228619cfdf7cc4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1795347Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63645}

src/debug/debug-scopes.cc

@@ -578,6 +578,11 @@ bool ScopeIterator::SetVariableValue(Handle<String> name,
 
 Handle<StringSet> ScopeIterator::GetNonLocals() { return non_locals_; }
 
+bool ScopeIterator::ClosureScopeHasThisReference() const {
+  return !closure_scope_->has_this_declaration() &&
+         closure_scope_->HasThisReference();
+}
+
 #ifdef DEBUG
 // Debug print of the content of the current scope.
 void ScopeIterator::DebugPrint() {

src/debug/debug-scopes.h

@@ -77,6 +77,8 @@ class ScopeIterator {
   // Set variable value and return true on success.
   bool SetVariableValue(Handle<String> variable_name, Handle<Object> new_value);
 
+  bool ClosureScopeHasThisReference() const;
+
   // Populate the set with collected non-local variable names.
   Handle<StringSet> GetNonLocals();
 

src/debug/debug-stack-trace-iterator.cc

@@ -87,13 +87,12 @@ v8::MaybeLocal<v8::Value> DebugStackTraceIterator::GetReceiver() const {
     // Arrow function defined in top level function without references to
     // variables may have NativeContext as context.
     if (!context->IsFunctionContext()) return v8::MaybeLocal<v8::Value>();
-    ScopeIterator scope_iterator(isolate_, frame_inspector_.get(),
-                                 ScopeIterator::COLLECT_NON_LOCALS);
+    ScopeIterator scope_iterator(isolate_, frame_inspector_.get());
     // We lookup this variable in function context only when it is used in arrow
     // function otherwise V8 can optimize it out.
-    if (!scope_iterator.GetNonLocals()->Has(isolate_,
-                                            isolate_->factory()->this_string()))
+    if (!scope_iterator.ClosureScopeHasThisReference()) {
       return v8::MaybeLocal<v8::Value>();
+    }
     DisallowHeapAllocation no_gc;
     VariableMode mode;
     InitializationFlag flag;
@@ -106,6 +105,7 @@ v8::MaybeLocal<v8::Value> DebugStackTraceIterator::GetReceiver() const {
     if (value->IsTheHole(isolate_)) return v8::MaybeLocal<v8::Value>();
     return Utils::ToLocal(value);
   }
+
   Handle<Object> value = frame_inspector_->GetReceiver();
   if (value.is_null() || (value->IsSmi() || !value->IsTheHole(isolate_))) {
     return Utils::ToLocal(value);