Redesigns the text input focus handling.

ui/views/widget/desktop_aura/x11_desktop_handler.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 "ui/views/widget/desktop_aura/x11_desktop_handler.h"
 
 #include <X11/Xatom.h>
 #include <X11/Xlib.h>
 
 #include "base/message_loop/message_loop.h"
@@ skipping 168 matching lines @@
 }
 
 void X11DesktopHandler::OnActiveWindowChanged(::Window xid) {
   if (current_window_ == xid)
     return;
   DesktopWindowTreeHostX11* old_host =
       views::DesktopWindowTreeHostX11::GetHostForXID(current_window_);
   if (old_host)
     old_host->HandleNativeWidgetActivationChanged(false);
 
+  current_window_ = xid;

[msw, 2014/03/11 00:58:50]

q: Why must the order of operations be changed here?

[Yuki, 2014/03/11 15:27:37]

I've added a comment.  The active widget must be changed before
HandleNativeWidgetActivationChanged(true) is called.

Handle...(false) behaves like Blur()
Handle...(true) behaves like Focus()
So between them, the active widget must be changed, so GetWidget()->IsActive()
returns the right value.

[msw, 2014/03/11 23:24:37]

Okay, this may have weird implications for code checking the active window
during this process; I guess any problems can be addressed if/when they arise.

[Yuki, 2014/03/12 09:13:15]

Will address any issues that would arise.

FocusManager checks if the widget is active or not during the call to
HandleNativeWidgetActivationChanged(), which indirectly calls
GetWidget()->GetFocusManager()->RestoreFocusedView().  At that time, the widget
must be active, otherwise the FocusManager won't set the focused view's
TextInputClient.

+
   DesktopWindowTreeHostX11* new_host =
       views::DesktopWindowTreeHostX11::GetHostForXID(xid);
   if (new_host)
     new_host->HandleNativeWidgetActivationChanged(true);
-
-  current_window_ = xid;
 }
 
 ::Window X11DesktopHandler::GetNextToActivateInStack(
     const std::vector< ::Window >& windows) {
   DCHECK(current_window_);
 
   // We start by doing a fast forward in the stack to find the active window.
   std::vector< ::Window >::const_iterator it =
       std::find(windows.begin(), windows.end(), current_window_);
 
@@ skipping 25 matching lines @@
     return *it;
   }
 
   // If we reached that point, that means we have not found an appropriate
   // window to activate. There is nothing we can do about it and the caller
   // should take care of doing the right thing.
   return 0;
 }
 
 }  // namespace views