Redesigns the text input focus handling.

ui/views/focus/focus_manager.cc

Index: ui/views/focus/focus_manager.cc
diff --git a/ui/views/focus/focus_manager.cc b/ui/views/focus/focus_manager.cc
index aba46e079ca754d507900c818265490b2713e6bc..1b61070f8a93ec5a07301b59fe8c96cd9435e3a0 100644
--- a/ui/views/focus/focus_manager.cc
+++ b/ui/views/focus/focus_manager.cc
@@ -11,6 +11,10 @@
 #include "base/logging.h"
 #include "build/build_config.h"
 #include "ui/base/accelerators/accelerator.h"
+#include "ui/base/ime/input_method.h"
+#include "ui/base/ime/text_input_client.h"
+#include "ui/base/ime/text_input_focus_manager.h"
+#include "ui/base/ui_base_switches_util.h"
 #include "ui/events/event.h"
 #include "ui/events/keycodes/keyboard_codes.h"
 #include "ui/views/focus/focus_manager_delegate.h"
@@ -117,6 +121,13 @@ bool FocusManager::OnKeyEvent(const ui::KeyEvent& event) {
   return true;
 }
 
+void FocusManager::OnTextInputClientChanged(View* view) {
+  if (view != focused_view_)

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

nit: reverse the condition and call Focus* in this block.

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

Done.

+    return;
+
+  FocusTextInputClient(view);
+}
+
 void FocusManager::ValidateFocusedView() {
   if (focused_view_ && !ContainsView(focused_view_))
     ClearFocus();
@@ -321,14 +332,18 @@ void FocusManager::SetFocusedViewWithReason(
 
   View* old_focused_view = focused_view_;
   focused_view_ = view;
-  if (old_focused_view)
+  if (old_focused_view) {
     old_focused_view->Blur();
+    BlurTextInputClient(old_focused_view);
+  }
   // Also make |focused_view_| the stored focus view. This way the stored focus
   // view is remembered if focus changes are requested prior to a show or while
   // hidden.
   SetStoredFocusView(focused_view_);
-  if (focused_view_)
+  if (focused_view_) {
+    FocusTextInputClient(focused_view_);
     focused_view_->Focus();
+  }
 
   FOR_EACH_OBSERVER(FocusChangeListener, focus_change_listeners_,
                     OnDidChangeFocus(old_focused_view, focused_view_));
@@ -537,4 +552,39 @@ bool FocusManager::ProcessArrowKeyTraversal(const ui::KeyEvent& event) {
   return false;
 }
 
+void FocusManager::FocusTextInputClient(View* view) {
+  if (!switches::IsNewTextInputFocusEnabled())
+    return;
+
+  // If the widget is not active, do not steal the text input focus.
+  if (!widget_->IsActive())
+    return;
+
+  ui::TextInputClient* text_input_client =
+      view ? view->GetTextInputClient() : NULL;
+  ui::TextInputFocusManager::GetInstance()->
+      SetFocusedTextInputClient(text_input_client);
+  ui::InputMethod* input_method = widget_->GetHostInputMethod();
+  if (input_method) {

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

Should this and BlurTextInputClient (or
TextInputFocusManager::SetFocusedTextInputClient) do the other stuff in
InputMethodBase::SetFocusedTextInputClientInternal? ie.
OnWillChangeFocusedClient, OnDidChangeFocusedClient, and
NotifyTextInputStateChanged.

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

Thre is nothing to do.

We call InputMethod::OnTextInputTypeChanged().  The text input type was
changed...  This means either of 1) the focus changed or 2) the same text input
has the focus, but the type changed (unlikely though).  All of concrete
implementations of ui::InputMethod treat this event as if the focused changed. 
So there is nothing to do as long as we call OnTextInputTypeChanged().  It's
enough.

We can remove On{Will,Did}ChangeFocusedClient(), etc. once the transition gets
done.

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

Sounds good.

+    input_method->OnTextInputTypeChanged(text_input_client);
+    input_method->OnCaretBoundsChanged(text_input_client);
+  }
+}
+
+void FocusManager::BlurTextInputClient(View* view) {
+  if (!switches::IsNewTextInputFocusEnabled())
+    return;
+
+  ui::TextInputClient* text_input_client =
+      view ? view->GetTextInputClient() : NULL;
+  if (text_input_client && text_input_client->HasCompositionText()) {
+    text_input_client->ConfirmCompositionText();
+    ui::InputMethod* input_method = widget_->GetHostInputMethod();
+    if (input_method && input_method->GetTextInputClient() == text_input_client)
+      input_method->CancelComposition(text_input_client);
+  }
+  ui::TextInputFocusManager::GetInstance()->
+      UnsetFocusedTextInputClient(text_input_client);
+}
+
 }  // namespace views