Chrome does not fire insertFromComposition events

[ianstormtaylor]

Chrome does not currently fire the proper beforeinput events when composing text. The Input Events Level 2 defines two events:

• insertFromComposition
• deleteByComposition

…which should be fired at the end of a composition to "commit" the results. And they should be cancellable. Chrome only fires the insertCompositionText and deleteCompositionText events which occur while the user is still in the process of composing, and are not cancelled (for good reason).

Here's the bug report (please star!):

• https://bugs.chromium.org/p/chromium/issues/detail?id=1022204

Without these events it's very hard to handle multi-character compositions properly. Whereas in Safari they are handled extremely easily since it fires these events.