arc/gio: Fix the Alt+Tab logic

Tab is used for Accessibility to focus on the menu button. After we
received the Tab press key event, we discarded it. Now we continue to
send Tab press event, which is consistent to Tab release key event. This
fixes the issue of after Alt+Tab focusing back to GIO window, the Search
key doesn't response.

Also reset the text input status when unregistering the window, which
fixes the issue of keys not responding after pressing Search.

Bug: b:239618743
Test: manual test to check if the bugs are reproducible.
Test: unittest
Change-Id: Ife145eebe5e2b9e08a2c11973b033cca0bde397e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3778325
Reviewed-by: David Jacobo <djacobo@chromium.org>
Auto-Submit: Cici Ruan <cuicuiruan@google.com>
Commit-Queue: Cici Ruan <cuicuiruan@google.com>
Cr-Commit-Position: refs/heads/main@{#1026529}

chrome/browser/ash/arc/input_overlay/arc_input_overlay_manager.cc

@@ -271,6 +271,7 @@ void ArcInputOverlayManager::UnRegisterWindow(aura::Window* window) {
   it->second->UnRegisterEventRewriter();
   RemoveDisplayOverlayController();
   RemoveObserverFromInputMethod();
+  it->second->NotifyTextInputState(false);
   registered_top_level_window_ = nullptr;
 }
 

chrome/browser/ash/arc/input_overlay/touch_injector.cc

@@ -462,7 +462,7 @@ ui::EventDispatchDetails TouchInjector::RewriteEvent(
       CleanupTouchEvents();
       display_overlay_controller_->SetDisplayMode(DisplayMode::kPreMenu);
     }
-    return DiscardEvent(continuation);
+    return SendEvent(continuation, &event);
   } else if (display_mode_ == DisplayMode::kPreMenu) {
     if (event.IsKeyEvent()) {
       auto* key_event = event.AsKeyEvent();