chromium/third_party/blink/web_tests/http/tests/inspector-protocol/main-target-commands-expected.txt

Tests for certain commands are only available at the top-level target
Page.captureSnapshot: Command can only be executed on top-level targets
Page.captureScreenshot: Command can only be executed on top-level targets
Page.startScreencast: Command can only be executed on top-level targets
Page.setDownloadBehavior: Command can only be executed on top-level targets