Make queryCommandSupported(copy|cut|paste) always return true
This patch makes |document.queryCommandSupported(name)| always return true for
"Copy", "Cut", and "Paste" commands to follow the editing API specification.
Before this patch, |queryCommandSupported()| returns value based on clipboard
accessibility, e.g. "clipboardRead" and "clipboardWrite" permission in Chrome
extensions. This behavior ins't compatible with the editing specification and
its intention. |queryCommandSupported()| should returns true for command
which can be passed to |execCommand()|, and other |queryCommandXXX()|.
Here is a table of return value of |execute()| and |isEnabled()| with
clipboard access permission and Editor.canCopy/Cut/Paste
Can R/W Editor.can isEnabled execute
Clipboard Copy/Paste
true true true true
true false false true
false true false false
false false false false
BUG=476508, 475868
TEST=LayoutTests/editing/pasteboard/copy-cut-paste-supported.html
Review URL: https://codereview.chromium.org/1406713002
Cr-Commit-Position: refs/heads/master@{#354240}
2 files changed
