Refactoring the ownership of ui::InputMethod.

ui/aura/window_tree_host.h

 // 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.
 
 #ifndef UI_AURA_WINDOW_TREE_HOST_H_
 #define UI_AURA_WINDOW_TREE_HOST_H_
 
 #include <vector>
 
 #include "base/event_types.h"
 #include "base/message_loop/message_loop.h"
 #include "ui/aura/aura_export.h"
 #include "ui/base/cursor/cursor.h"
+#include "ui/base/ime/input_method_delegate.h"
 #include "ui/events/event_source.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace gfx {
 class Insets;
 class Point;
 class Rect;
 class Size;
 class Transform;
 }
 
 namespace ui {
 class Compositor;
 class EventProcessor;
+class InputMethod;
 class ViewProp;
 }
 
 namespace aura {
 namespace test {
 class WindowTreeHostTestApi;
 }
 
 class WindowEventDispatcher;
 class WindowTreeHostObserver;
 
 // WindowTreeHost bridges between a native window and the embedded RootWindow.
 // It provides the accelerated widget and maps events from the native os to
 // aura.
-class AURA_EXPORT WindowTreeHost {
+class AURA_EXPORT WindowTreeHost : public ui::internal::InputMethodDelegate,
+                                   public ui::EventSource {
  public:
-  virtual ~WindowTreeHost();
+  ~WindowTreeHost() override;
 
   // Creates a new WindowTreeHost. The caller owns the returned value.
   static WindowTreeHost* Create(const gfx::Rect& bounds);
 
   // Returns the WindowTreeHost for the specified accelerated widget, or NULL
   // if there is none associated.
   static WindowTreeHost* GetForAcceleratedWidget(gfx::AcceleratedWidget widget);
 
   void InitHost();
 
@@ skipping 54 matching lines @@
   void OnCursorVisibilityChanged(bool visible);
 
   // Moves the cursor to the specified location relative to the root window.
   void MoveCursorTo(const gfx::Point& location);
 
   // Moves the cursor to the |host_location| given in host coordinates.
   void MoveCursorToHostLocation(const gfx::Point& host_location);
 
   gfx::NativeCursor last_cursor() const { return last_cursor_; }
 
+  // Gets the InputMethod instance, if NULL, creates & owns it.
+  ui::InputMethod* GetInputMethod();
+
+  // Sets a shared unowned InputMethod. This is used when there is a singleton
+  // InputMethod shared between multiple WindowTreeHost instances.
+  //
+  // This is used for Ash only. There are 2 reasons:
+  // 1) ChromeOS virtual keyboard needs to receive ShowImeIfNeeded notification
+  // from InputMethod. Multiple InputMethod instances makes it hard to
+  // register/unregister the observer for that notification.
+  // 2) For Ozone, there is no native focus state for the root window and
+  // WindowTreeHost. See DrmWindowHost::CanDispatchEvent, the key events always
+  // goes to the primary WindowTreeHost. And after InputMethod processed the key
+  // event and continue dispatching it, WindowTargeter::FindTargetForEvent may
+  // re-dispatch it to a different WindowTreeHost. So the singleton InputMethod
+  // can make sure the correct InputMethod instance processes the key event no
+  // matter which WindowTreeHost is the target for event. Please refer to the
+  // test: ExtendedDesktopTest.KeyEventsOnLockScreen.
+  //
+  // TODO(shuchen): remove this method after above reasons become invalid.
+  // A possible solution is to make sure DrmWindowHost can find the correct
+  // WindowTreeHost to dispatch events.
+  void SetSharedInputMethod(ui::InputMethod* input_method);
+
+  // Overridden from ui::internal::InputMethodDelegate:
+  bool DispatchKeyEventPostIME(const ui::KeyEvent& event) override;
+
   // Returns the EventSource responsible for dispatching events to the window
   // tree.
   virtual ui::EventSource* GetEventSource() = 0;
 
   // Returns the accelerated widget.
   virtual gfx::AcceleratedWidget GetAcceleratedWidget() = 0;
 
   // Shows the WindowTreeHost.
   void Show();
 
@@ skipping 36 matching lines @@
 
   // kCalled when the cursor visibility has changed.
   virtual void OnCursorVisibilityChangedNative(bool show) = 0;
 
   // Shows the WindowTreeHost.
   virtual void ShowImpl() = 0;
 
   // Hides the WindowTreeHost.
   virtual void HideImpl() = 0;
 
+  // Overridden from ui::EventSource:
+  ui::EventProcessor* GetEventProcessor() override;
+  ui::EventDispatchDetails DeliverEventToProcessor(ui::Event* event) override;
+
  private:
   friend class test::WindowTreeHostTestApi;
 
   // Moves the cursor to the specified location. This method is internally used
   // by MoveCursorTo() and MoveCursorToHostLocation().
   void MoveCursorToInternal(const gfx::Point& root_location,
                             const gfx::Point& host_location);
 
   // We don't use a scoped_ptr for |window_| since we need this ptr to be valid
   // during its deletion. (Window's dtor notifies observers that may attempt to
   // reach back up to access this object which will be valid until the end of
   // the dtor).
   Window* window_;  // Owning.
 
   base::ObserverList<WindowTreeHostObserver> observers_;
 
   scoped_ptr<WindowEventDispatcher> dispatcher_;
 
   scoped_ptr<ui::Compositor> compositor_;
 
   // Last cursor set.  Used for testing.
   gfx::NativeCursor last_cursor_;
   gfx::Point last_cursor_request_position_in_host_;
 
   scoped_ptr<ui::ViewProp> prop_;
 
+  // The InputMethod instance used to process key events.
+  // If owned it, it is created in GetInputMethod() method;
+  // If not owned it, it is passed in through SetSharedInputMethod() method.
+  ui::InputMethod* input_method_;
+
+  // Whether the InputMethod instance is owned by this WindowTreeHost.
+  bool owned_input_method_;
+
   DISALLOW_COPY_AND_ASSIGN(WindowTreeHost);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_TREE_HOST_H_