[DevTools] Do not debug worker shadow pages

This change breaks pausing on start when inspecting a shared worker that
gets reloaded. More detail here: crbug.com/987024

Bug: 882467
Change-Id: I074b547996fd7f11d835fcebfdae32a4f7063a9f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1636110
Commit-Queue: Hiroki Nakagawa <nhiroki@chromium.org>
Commit-Queue: Kenichi Ishibashi <bashi@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#685152}
61 files changed