Speed up StackTraceFrame::GetScriptNameOrSourceUrl()

This retrieves script name directly from StackFrameBase, bypassing
building of StackFrameInfo if one hasn't already been initialized,
thus avoiding computation of expensive properties that are not
required.

Bug: chromium:1057211
Change-Id: I91eaecdbaee6f5834a02d70e2df872e82998ab83
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2080663
Commit-Queue: Andrey Kosyakov <caseq@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66600}

src/objects/stack-frame-info.cc

@@ -71,8 +71,23 @@ Handle<Object> StackTraceFrame::GetFileName(Handle<StackTraceFrame> frame) {
 // static
 Handle<Object> StackTraceFrame::GetScriptNameOrSourceUrl(
     Handle<StackTraceFrame> frame) {
-  auto name = GetFrameInfo(frame)->script_name_or_source_url();
-  return handle(name, frame->GetIsolate());
+  Isolate* isolate = frame->GetIsolate();
+  // TODO(caseq, szuend): the logic below is a workaround for crbug.com/1057211.
+  // We should probably have a dedicated API for the scenario described in the
+  // bug above and make getters of this class behave consistently.
+  // See https://bit.ly/2wkbuIy for further discussion.
+  // Use FrameInfo if it's already there, but avoid initializing it for just
+  // the script name, as it is much more expensive than just getting this
+  // directly.
+  if (!frame->frame_info().IsUndefined()) {
+    auto name = GetFrameInfo(frame)->script_name_or_source_url();
+    return handle(name, isolate);
+  }
+  FrameArrayIterator it(isolate,
+                        handle(FrameArray::cast(frame->frame_array()), isolate),
+                        frame->frame_index());
+  DCHECK(it.HasFrame());
+  return it.Frame()->GetScriptNameOrSourceUrl();
 }
 
 // static