This is a follow up to the bug 53031. Since we no longer calls EditorClient::contentIsEditable to determine whether or not a document is editable, this member function needs to be removed from EditorClient. Also, this feature has been a performance bottleneck for the editing component (see the bug 53649).
*** Bug 54052 has been marked as a duplicate of this bug. ***
Bug taken. :)
*** This bug has been marked as a duplicate of bug 54292 ***