components: Fix 'gn check' errors for undo and webcrypto.

Tested on Linux with the following command lines:

$ gn gen out-gn/Debug
$ gn check out-gn/Debug //components/undo/*
$ gn check out-gn/Debug //components/webcrypto/*

BUG=367595, 376000
TEST=see above
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Review URL: https://codereview.chromium.org/1183773005

Cr-Commit-Position: refs/heads/master@{#334826}
3 files changed