Redesigns the text input focus handling.

ui/wm/core/focus_controller.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/wm/core/focus_controller.h"
 
 #include "base/auto_reset.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/client/focus_change_observer.h"
 #include "ui/aura/env.h"
 #include "ui/aura/window_tracker.h"
+#include "ui/base/ime/text_input_focus_manager.h"
 #include "ui/events/event.h"
 #include "ui/wm/core/focus_rules.h"
 #include "ui/wm/core/window_util.h"
 #include "ui/wm/public/activation_change_observer.h"
 
 namespace wm {
 namespace {
 
 // When a modal window is activated, we bring its entire transient parent chain
 // to the front. This function must be called before the modal transient is
@@ skipping 200 matching lines @@
 
 void FocusController::SetFocusedWindow(aura::Window* window) {
   if (updating_focus_ || window == focused_window_)
     return;
   DCHECK(rules_->CanFocusWindow(window));
   if (window)
     DCHECK_EQ(window, rules_->GetFocusableWindow(window));
 
   base::AutoReset<bool> updating_focus(&updating_focus_, true);
   aura::Window* lost_focus = focused_window_;
+
+  // |window| is going to get the focus, so reset the text input client.
+  // OnWindowFocused() may set a proper text input client if the implementation
+  // supports text input.
+  ui::TextInputFocusManager* text_input_focus_manager =
+      ui::TextInputFocusManager::GetInstance();
+  if (window)
+    text_input_focus_manager->FocusTextInputClient(NULL);
+
   // Allow for the window losing focus to be deleted during dispatch. If it is
   // deleted pass NULL to observers instead of a deleted window.
   aura::WindowTracker window_tracker;
   if (lost_focus)
     window_tracker.Add(lost_focus);
   if (focused_window_ && observer_manager_.IsObserving(focused_window_) &&
       focused_window_ != active_window_) {
     observer_manager_.Remove(focused_window_);
   }
   focused_window_ = window;
@@ skipping 11 matching lines @@
     if (observer)
       observer->OnWindowFocused(focused_window_, lost_focus);
   }
   aura::client::FocusChangeObserver* observer =
       aura::client::GetFocusChangeObserver(focused_window_);
   if (observer) {
     observer->OnWindowFocused(
         focused_window_,
         window_tracker.Contains(lost_focus) ? lost_focus : NULL);
   }
+
+  // Ensure that the text input client is reset when the window loses the focus.
+  if (!window)
+    text_input_focus_manager->FocusTextInputClient(NULL);

[msw, 2014/05/02 18:46:03]

nit: the value of |window| doesn't change from line 240, afaict. Is it possible
to just call text_input_focus_manager->FocusTextInputClient(NULL); once above,
regardless of the value of |window|? Perhaps I'm missing some nuance here.

[Yuki, 2014/05/07 05:58:02]

Some observers above might change the focused text input client (if so, it must
be NULL though), we'd like to make sure here that the focused text input client
is NULL when losing the window focus regardless of observer's behavior.

 }
 
 void FocusController::SetActiveWindow(aura::Window* requested_window,
                                       aura::Window* window) {
   if (updating_activation_)
     return;
 
   if (window == active_window_) {
     if (requested_window) {
       FOR_EACH_OBSERVER(aura::client::ActivationChangeObserver,
@@ skipping 70 matching lines @@
 
 void FocusController::WindowFocusedFromInputEvent(aura::Window* window) {
   // Only focus |window| if it or any of its parents can be focused. Otherwise
   // FocusWindow() will focus the topmost window, which may not be the
   // currently focused one.
   if (rules_->CanFocusWindow(GetToplevelWindow(window)))
     FocusWindow(window);
 }
 
 }  // namespace wm