compositionstart event's data should contain text to replace.

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

Index: LayoutTests/fast/events/ime-composition-events-001.html
diff --git a/LayoutTests/fast/events/ime-composition-events-001.html b/LayoutTests/fast/events/ime-composition-events-001.html
index 8b232f67e73c42bf91a20c864257467747d9108d..1a5e59625fcdc3b5791e6babe3c3be81efd5125e 100644
--- a/LayoutTests/fast/events/ime-composition-events-001.html
+++ b/LayoutTests/fast/events/ime-composition-events-001.html
@@ -57,6 +57,18 @@ if (window.testRunner) {
         textInputController.setMarkedText('9', 0, 1);
         textInputController.unmarkText();
     }
+
+    // Case 5: Compose a text on selection and commit it.
+    test.value = 'I have a pen';
+    test.selectionStart = 2;
+    test.selectionEnd = 6;
+    textInputController.setMarkedText('lost', 0, 1);
+    textInputController.insertText('made');
+    if (test.value == 'I made a pen') {
+        log('SUCCESS: ' + test.value);
+    } else {
+        log('FAILURE: ' + test.value + ' is not "I made a pen".');
+    }
 }
 </script>
 </body>