[Android] Synthetic composition event should have DomKey 'Unidentified'

content/browser/renderer_host/input/web_input_event_builders_android.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/input/web_input_event_builders_android.h"
 
 #include <android/input.h>
 
 #include "base/logging.h"
 #include "content/browser/renderer_host/input/web_input_event_util.h"
@@ skipping 27 matching lines @@
     android_modifier |= AMETA_CAPS_LOCK_ON;
   return android_modifier;
 }
 
 ui::DomKey GetDomKeyFromEvent(
     JNIEnv* env,
     const base::android::JavaRef<jobject>& android_key_event,
     int keycode,
     int modifiers,
     int unicode_character) {
+  // Synthetic key event, not enough information to get DomKey.
+  if (android_key_event.is_null() && !unicode_character)
+    return ui::DomKey::UNIDENTIFIED;

[chongz, 2016/03/17 15:50:39]

Sorry for the confusing logic... Will this look better?
If the event came from |setComposingText()| or it's a synthetic |Char| event
|android_key_event| will be null, otherwise we should have |android_key_event|
if it came from |sendKeyEvent()|.

For 229 if it's AKEYCODE_LAST_CHANNEL it should come from |sendKeyEvent()| and
has |android_key_event|.

However I'm not able to find a hardware with the key (seems to be some kind of
TV remote?) to test, but I've added a pair of unit tests, hope it would be good.

Thanks!

+
   if (!unicode_character && env) {
     // According to spec |kAllowedModifiers| should be Shift and AltGr, however
     // Android doesn't have AltGr key and ImeAdapter::getModifiers won't pass it
     // either.
     // According to discussion we want to honor CapsLock and possibly NumLock as
     // well. https://github.com/w3c/uievents/issues/70
     const int kAllowedModifiers =
         WebInputEvent::ShiftKey | WebInputEvent::CapsLockOn;
     int fallback_modifiers =
         WebInputEventToAndroidModifier(modifiers & kAllowedModifiers);
@@ skipping 115 matching lines @@
   result.type = type;
   result.x = x;
   result.y = y;
   result.timeStampSeconds = time_sec;
   result.sourceDevice = blink::WebGestureDeviceTouchscreen;
 
   return result;
 }
 
 }  // namespace content