Introduce InsertIncrementalTextCommand to respect existing style for composition

third_party/WebKit/LayoutTests/fast/events/ime-composition-events-001.html

Index: third_party/WebKit/LayoutTests/fast/events/ime-composition-events-001.html
diff --git a/third_party/WebKit/LayoutTests/fast/events/ime-composition-events-001.html b/third_party/WebKit/LayoutTests/fast/events/ime-composition-events-001.html
index 56de7027e15eac25c2666eee84a6f0581a8ef23f..e6e8292a36a50442f70f63adfffddccf842dc9b4 100644
--- a/third_party/WebKit/LayoutTests/fast/events/ime-composition-events-001.html
+++ b/third_party/WebKit/LayoutTests/fast/events/ime-composition-events-001.html
@@ -24,8 +24,13 @@ function logCompositionEnd(event) {
     testPassed('event.data is "' + event.data + '"');
 }
 

[yabinh, 2016/11/25 04:36:27]

Replacing textInput event with beforeinput and input events because:
"
The textInput event, originally proposed as a replacement for keypress, was
removed in favor of the current beforeinput and input events.
"
(https://www.w3.org/TR/uievents/#event-flow)

[chongz, 2016/11/28 16:01:04]

I think we cannot simply remove 'textInput' event as it will break the web,
please see comments in |InputMethodController|.

[yabinh, 2016/12/02 08:41:55]

'textInput' event is kept in patch set 3 and 4.

-function logTextInput(event) {
-    shouldBeEqualToString('event.type', 'textInput');
+function logBeforeInput(event) {
+    shouldBeEqualToString('event.type', 'beforeinput');
+    testPassed('event.data is "' + event.data + '"');
+}
+
+function logInput(event) {
+    shouldBeEqualToString('event.type', 'input');
     testPassed('event.data is "' + event.data + '"');
 }
 
@@ -36,7 +41,8 @@ test.focus();
 test.addEventListener('compositionstart', logCompositionStart, false);
 test.addEventListener('compositionupdate', logCompositionUpdate, false);
 test.addEventListener('compositionend', logCompositionEnd, false);
-test.addEventListener('textInput', logTextInput, false);
+test.addEventListener('beforeinput', logBeforeInput, false);
+test.addEventListener('input', logInput, false);
 
 // Case 1: Compose a text and commit it.
 textInputController.setMarkedText('1', 0, 1);