Currently, copy/cut/paste is always enabled for HTML or XHTML so events get dispatched (bug 1159490). XUL supports enabling/disabling these commands, but it'd be nice to support that for any chrome document.

See more discussion in https://bugzilla.mozilla.org/show_bug.cgi?id=1178047#c18

For content HTML/XHTML copy/paste should always be enabled, but for chrome
docs we can support enabling/disabling copy/paste.

Also, restores tests to how they were before copy/paste was always enabled.

Backed out for dt failures on browser_console_context_menu_entries.js

Backout link: https://hg.mozilla.org/integration/autoland/rev/22b5dd1aea554ad662228bc6253b16fea3e46207
Push link: https://treeherder.mozilla.org/#/jobs?repo=autoland&resultStatus=pending%2Crunning%2Csuccess%2Ctestfailed%2Cbusted%2Cexception%2Crunnable&searchStr=os%2Cx%2C10.14%2Cdebug%2Cmochitests%2Ctest-macosx1014-64%2Fdebug-mochitest-devtools-chrome-e10s-5%2Cm%28dt5%29&revision=aa7f507ac74362abce9fda28f503851e53ea163b&selectedJob=251819678
Log link: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=251819678&repo=autoland&lineNumber=3510

Hmm....looks like whether paste is enabled/disabled on MacOS isn't reliable. I'll need to update that test to be like the other context menu tests and only check paste on Windows.

Backed out changeset 7312aba8ec3b (bug 1558674) for causing browser_console_context_menu_entries.js to permafail

push that caused the backout: https://treeherder.mozilla.org/#/jobs?repo=autoland&revision=7312aba8ec3b2149f5251bd91d8f1cfee7cd3322

failure: https://treeherder.mozilla.org/#/jobs?repo=autoland&selectedJob=252004342&fromchange=b26a70a0fe8f22ee4a5118c7c563ab98a115e692&searchStr=windows%2C10%2Cx64%2Casan%2Cmochitests%2Ctest-windows10-64-asan%2Fopt-mochitest-devtools-chrome-e10s-8%2Cm%28dt8%29

backout: https://hg.mozilla.org/integration/autoland/rev/dd19d57a81d5690fccd5e45be09e3b8686d79e53

https://hg.mozilla.org/mozilla-central/rev/a107e0c09120