Makes sure the keyboard typing isn't blocked when InputMethod::OnFocus() is not correctly called.

ui/base/ime/input_method_auralinux.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 "ui/base/ime/input_method_auralinux.h"
 
 #include "base/auto_reset.h"
 #include "base/environment.h"
 #include "ui/base/ime/linux/linux_input_method_context_factory.h"
 #include "ui/base/ime/text_input_client.h"
@@ skipping 28 matching lines @@
 
 bool InputMethodAuraLinux::OnUntranslatedIMEMessage(
     const base::NativeEvent& event,
     NativeEventResult* result) {
   return false;
 }
 
 void InputMethodAuraLinux::DispatchKeyEvent(ui::KeyEvent* event) {
   DCHECK(event->type() == ET_KEY_PRESSED || event->type() == ET_KEY_RELEASED);
   DCHECK(system_toplevel_window_focused());
+  if (!system_toplevel_window_focused()) {

[sky, 2016/01/08 16:51:57]

I think you should see if the toplevel is actually active when we get a key
event like this.

[Shu Chen, 2016/01/09 01:46:02]

Line 1530 of desktop_window_tree_host_x11.cc makes sure DispatchKeyEvent is
called only when Widget::IsActive() returns true.

To check the window state at X11 level, do you know the XWindow API to do that?

+    LOG(ERROR) << "Key event got without the top-level window being activated.";
+    GetLogCollector()->OutputLogs();
+    // There are random issues that the keyboard typing doesn't work.
+    // The root cause might be the InputMethod::OnFocus() is not correctly
+    // called when the top-level window is activated
+    // (in DNWA::HandleActivationChanged).
+    // Calls OnFocus here to unblock the keyboard typing.
+    OnFocus();
+  } else {
+    GetLogCollector()->ClearLogs();
+  }
 
   // If no text input client, do nothing.
   if (!GetTextInputClient()) {
     ignore_result(DispatchKeyEventPostIME(event));
     return;
   }
 
   suppress_next_result_ = false;
   composition_changed_ = false;
   result_text_.clear();
@@ skipping 300 matching lines @@
 
 void InputMethodAuraLinux::ConfirmCompositionText() {
   TextInputClient* client = GetTextInputClient();
   if (client && client->HasCompositionText())
     client->ConfirmCompositionText();
 
   ResetContext();
 }
 
 }  // namespace ui