Fix OSK flickering issue

content/renderer/render_widget.cc

 // Copyright (c) 2012 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/renderer/render_widget.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 1041 matching lines @@
   base::AutoReset<WebInputEvent::Type> handling_event_type_resetter(
       &handling_event_type_, input_event->type);
 
   // Calls into |didOverscroll()| while handling this event will populate
   // |event_overscroll|, which in turn will be bundled with the event ack.
   scoped_ptr<DidOverscrollParams> event_overscroll;
   base::AutoReset<scoped_ptr<DidOverscrollParams>*>
       handling_event_overscroll_resetter(&handling_event_overscroll_,
                                          &event_overscroll);
 
 #if defined(OS_ANDROID)

[aelias_OOO_until_Jul13, 2015/10/22 00:07:56]

Let's delete this OS_ANDROID.

[Changwan Ryu, 2015/10/22 02:46:00]

Done. (try is still running).

   // On Android, when a key is pressed or sent from the Keyboard using IME,
   // |AdapterInputConnection| generates input key events to make sure all JS
   // listeners that monitor KeyUp and KeyDown events receive the proper key
   // code. Since this input key event comes from IME, we need to set the
   // IME event guard here to make sure it does not interfere with other IME
   // events.
   scoped_ptr<ImeEventGuard> ime_event_guard_maybe;

[aelias_OOO_until_Jul13, 2015/10/22 00:07:56]

We can unconditionally create the IME guard here, not just for keyboard events. 
(And we can remove the shortlist of "special" keys, it looks like those are just
fixing the problem of show_ime state getting lost, which I suggest another fix
for below.)

[Changwan Ryu, 2015/10/22 02:46:00]

This is a great idea! In order to implement it I had to make
StartHandlingImeEvent / FinishHandlingImeEvent nestable.

   if (WebInputEvent::isKeyboardEventType(input_event->type)) {
     const WebKeyboardEvent& key_event =
         *static_cast<const WebKeyboardEvent*>(input_event);
     // Some keys are special and it's essential that no events get blocked.
     if (key_event.nativeKeyCode != AKEYCODE_TAB &&
         key_event.nativeKeyCode != AKEYCODE_DPAD_CENTER &&
         key_event.nativeKeyCode != AKEYCODE_DPAD_LEFT &&
         key_event.nativeKeyCode != AKEYCODE_DPAD_RIGHT &&
         key_event.nativeKeyCode != AKEYCODE_DPAD_UP &&
         key_event.nativeKeyCode != AKEYCODE_DPAD_DOWN)
@@ skipping 799 matching lines @@
   UpdateSelectionBounds();
 #if defined(OS_ANDROID)
   UpdateTextInputState(NO_SHOW_IME, FROM_IME);
 #endif
 }
 
 void RenderWidget::UpdateTextInputState(ShowIme show_ime,
                                         ChangeSource change_source) {
   TRACE_EVENT0("renderer", "RenderWidget::UpdateTextInputState");
   if (handling_ime_event_)
     return;

[aelias_OOO_until_Jul13, 2015/10/22 00:07:56]

Prior to this early return, I think we should do 'need_show_ime_ |= (show_ime ==
SHOW_IME_IF_NEEDED); text_field_is_dirty_ |= (change_source == FROM_NON_IME);'. 
Otherwise a show request could be lost.

[Changwan Ryu, 2015/10/22 02:46:00]

Hmm... Since we do not store show_ime_, I came up with
pending_show_ime_if_needed_ so that show_ime in an ignored state update can be
stored.

-  ui::TextInputType new_type = GetTextInputType();
+
+  // We could be called in the middle of focus change, or in some other
+  // intermediary state.
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::Bind(&RenderWidget::UpdateTextInputStateInternal, this,
+                            show_ime, change_source));
+}
+
+void RenderWidget::UpdateTextInputStateInternal(ShowIme show_ime,
+                                                ChangeSource change_source) {
+  blink::WebTextInputInfo new_info;
+  if (webwidget_)
+    new_info = webwidget_->textInputInfo();
+
+  ui::TextInputType new_type = WebKitToUiTextInputType(new_info.type);
   if (IsDateTimeInput(new_type))
     return;  // Not considered as a text input field in WebKit/Chromium.
 
-  blink::WebTextInputInfo new_info;
-  if (webwidget_)
-    new_info = webwidget_->textInputInfo();
   const ui::TextInputMode new_mode = ConvertInputMode(new_info.inputMode);
 
   bool new_can_compose_inline = CanComposeInline();
 
   // Only sends text input params if they are changed or if the ime should be
   // shown.
   if (show_ime == SHOW_IME_IF_NEEDED ||
       (text_input_type_ != new_type ||
        text_input_mode_ != new_mode ||
        text_input_info_ != new_info ||
@@ skipping 475 matching lines @@
 void RenderWidget::RegisterVideoHoleFrame(RenderFrameImpl* frame) {
   video_hole_frames_.AddObserver(frame);
 }
 
 void RenderWidget::UnregisterVideoHoleFrame(RenderFrameImpl* frame) {
   video_hole_frames_.RemoveObserver(frame);
 }
 #endif  // defined(VIDEO_HOLE)
 
 }  // namespace content