Remove the 2-level input method system & InputMethodBridge.

ui/views/controls/tree/tree_view.h

Index: ui/views/controls/tree/tree_view.h
diff --git a/ui/views/controls/tree/tree_view.h b/ui/views/controls/tree/tree_view.h
index 0cb3760333765806efd07860dd0da01d7d02de74..c0d9742bf7344461ba84b37e3123e6d4b28d7764 100644
--- a/ui/views/controls/tree/tree_view.h
+++ b/ui/views/controls/tree/tree_view.h
@@ -119,12 +119,13 @@ class VIEWS_EXPORT TreeView : public ui::TreeModelObserver,
 
   views::Textfield* editor() { return editor_; }
 
+  ui::TextInputClient* GetTextInputClient();
+
   // View overrides:
   void Layout() override;
   gfx::Size GetPreferredSize() const override;
   bool AcceleratorPressed(const ui::Accelerator& accelerator) override;
   bool OnMousePressed(const ui::MouseEvent& event) override;
-  ui::TextInputClient* GetTextInputClient() override;
   void OnGestureEvent(ui::GestureEvent* event) override;
   void ShowContextMenu(const gfx::Point& p,
                        ui::MenuSourceType source_type) override;