We'll start to dispatch keydown event and keyup event even during composition.
So, for testing those events won't break our UI, we should make
EventUtils.synhtesizeComposition() and EventUtils.synthesizeCompositionChange()
dispatch keydown event and keyup event even if callers don't specify keyboard
event explicitly.
Typically, "keydown" event is marked as "processed by IME", i.e., keyCode
value is set to DOM_VK_PROCESSKEY and key is set to "Process", with our
widget which handles native IME and key input. On the other hand, "keyup"
is NOT marked as so.
Therefore, this patch makes TextInputProcessor emulates this behavior without
any new special flags. And for making possible to emulate special cases,
this patch adds two flags to nsITextInputProcessor. One is
KEY_DONT_MARK_KEYDOWN_AS_PROCESSED. The other is KEY_MARK_KEYUP_AS_PROCESSED.
Unfortunately, those flags have opposite meaning but this must be better than
making necessary to one flag for emulating usual keydown/keyup events.
Finally, this makes some tests specify better keyboard information to
synthesizeComposition() and synthesizeCompositionChange() to emulate
actual keyboard events during composition.
MozReview-Commit-ID: ItYaXILkNQE
