KeyboardEvent doesn't bring actual character input

[DartBot]

This issue was originally filed by li....@intel.com

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What steps will reproduce the problem?
1.
2.
3.

What is the expected output? What do you see instead?
Create a keyboard event, and dispatch it to specified DOM node, it works fine, the dom node can receive the keyboard event, but it doesn't bring actual char input, which is different from actual keyboard event.

What version of the product are you using? On what operating system?
I am using trunk building, chromium M33

Please provide any additional information below.
Sample Code:
<input type="text" id="name">
var name = document.getElementById("name");
name.onkeydown = function(event) {
  var keyEvent = document.createEvent("KeyboardEvents");
  keyEvent.initKeyboardEvent("keydown", event.bubbles, event.cancelable, event.view,
      event.keyIdentifier, event.location, event.ctrlKey, event.altKey,
      event.shiftKey, event.metaKey, event.altGraphKey);
  name.dispatchEvent(keyEvent);
  name.onkeydown = null;
}

If I input "a" char to the input node, I think "aa" should be displayed, since both real and virtual keyboard event are dispatched, but I just saw "a" in the input node.

[DartBot]

This comment was originally written by li....@intel.com

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I don't know whether the difference of actual and simulated keyboard event was discussed or not.

[iposva-google]

Added Area-Dart2JS, Triaged labels.

[kasperl]

Removed Area-Dart2JS label.
Added Area-HTML label.

[blois]

cc @efortuna.

[kevmoo]

Removed Area-HTML label.
Added Area-Library, Library-Html labels.

[efortuna]

Added Duplicate label.
Marked as being merged into #13902.