Added a system caret used for accessibility on Windows.

ui/views/win/hwnd_message_handler.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_VIEWS_WIN_HWND_MESSAGE_HANDLER_H_
 #define UI_VIEWS_WIN_HWND_MESSAGE_HANDLER_H_
 
 #include <windows.h>
 
 #include <stddef.h>
 #include <map>
 #include <memory>
 #include <set>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/lazy_instance.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/strings/string16.h"
 #include "base/win/scoped_gdi_object.h"
 #include "base/win/win_util.h"
 #include "ui/accessibility/ax_enums.h"
+#include "ui/base/ime/input_method_observer.h"
 #include "ui/base/ui_base_types.h"
 #include "ui/base/win/window_event_target.h"
 #include "ui/events/event.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/sequential_id_generator.h"
 #include "ui/gfx/win/window_impl.h"
 #include "ui/views/views_export.h"
 
 namespace gfx {
 class ImageSkia;
 class Insets;
 namespace win {
 class DirectManipulationHelper;
 }  // namespace win
 }  // namespace gfx
 
 namespace ui  {
+class AXSystemCaretWin;
+class InputMethod;
+class TextInputClient;
 class ViewProp;
 }
 
 namespace views {
 
 class FullscreenHandler;
 class HWNDMessageHandlerDelegate;
 class WindowsSessionChangeObserver;
 
 // These two messages aren't defined in winuser.h, but they are sent to windows
@@ skipping 59 matching lines @@
     bHandled; \
     switch(dwMsgMapID) { \
       case 0:
 
 // An object that handles messages for a HWND that implements the views
 // "Custom Frame" look. The purpose of this class is to isolate the windows-
 // specific message handling from the code that wraps it. It is intended to be
 // used by both a views::NativeWidget and an aura::WindowTreeHost
 // implementation.
 // TODO(beng): This object should eventually *become* the WindowImpl.
-class VIEWS_EXPORT HWNDMessageHandler :
-    public gfx::WindowImpl,
-    public ui::WindowEventTarget {
+class VIEWS_EXPORT HWNDMessageHandler : public gfx::WindowImpl,
+                                        public ui::InputMethodObserver,
+                                        public ui::WindowEventTarget {
  public:
   explicit HWNDMessageHandler(HWNDMessageHandlerDelegate* delegate);
   ~HWNDMessageHandler() override;
 
   void Init(HWND parent, const gfx::Rect& bounds);
   void InitModalType(ui::ModalType modal_type);
 
   void Close();
   void CloseNow();
 
@@ skipping 87 matching lines @@
 
  private:
   typedef std::set<DWORD> TouchIDs;
   enum class DwmFrameState { OFF, ON };
 
   // Overridden from WindowImpl:
   HICON GetDefaultWindowIcon() const override;
   HICON GetSmallWindowIcon() const override;
   LRESULT OnWndProc(UINT message, WPARAM w_param, LPARAM l_param) override;
 
+  // Overridden from InputMethodObserver
+  void OnTextInputTypeChanged(const ui::TextInputClient* client) override;
+  void OnFocus() override;
+  void OnBlur() override;
+  void OnCaretBoundsChanged(const ui::TextInputClient* client) override;
+  void OnTextInputStateChanged(const ui::TextInputClient* client) override;
+  void OnInputMethodDestroyed(const ui::InputMethod* input_method) override;
+  void OnShowImeIfNeeded() override;
+
   // Overridden from WindowEventTarget
   LRESULT HandleMouseMessage(unsigned int message,
                              WPARAM w_param,
                              LPARAM l_param,
                              bool* handled) override;
   LRESULT HandleKeyboardMessage(unsigned int message,
                                 WPARAM w_param,
                                 LPARAM l_param,
                                 bool* handled) override;
   LRESULT HandleTouchMessage(unsigned int message,
@@ skipping 327 matching lines @@
   // Checks if there is a full screen window on the same monitor as the
   // |window| which is becoming active. If yes then we reduce the size of the
   // fullscreen window by 1 px to ensure that maximized windows on the same
   // monitor don't draw over the taskbar.
   void CheckAndHandleBackgroundFullscreenOnMonitor(HWND window);
 
   // Provides functionality to reduce the bounds of the fullscreen window by 1
   // px on activation loss to a window on the same monitor.
   void OnBackgroundFullscreen();
 
+  // Deletes the system caret used for accessibility. This will result in any
+  // clients that are still holding onto its |IAccessible| to get a failure code
+  // if they request its location.
+  void DestroyAXSystemCaret();
+
   HWNDMessageHandlerDelegate* delegate_;
 
   std::unique_ptr<FullscreenHandler> fullscreen_handler_;
 
   // Set to true in Close() and false is CloseNow().
   bool waiting_for_close_now_;
 
   bool use_system_default_icon_;
 
   // Whether all ancestors have been enabled. This is only used if is_modal_ is
@@ skipping 104 matching lines @@
   bool sent_window_size_changing_;
 
   // This is used to keep track of whether a WM_WINDOWPOSCHANGED has
   // been received after the WM_WINDOWPOSCHANGING.
   uint32_t current_window_size_message_ = 0;
 
   // Manages observation of Windows Session Change messages.
   std::unique_ptr<WindowsSessionChangeObserver>
       windows_session_change_observer_;
 
+  // Some assistive software need to track the location of the caret.
+  std::unique_ptr<ui::AXSystemCaretWin> ax_system_caret_;
+
   // This class provides functionality to register the legacy window as a
   // Direct Manipulation consumer. This allows us to support smooth scroll
   // in Chrome on Windows 10.
   std::unique_ptr<gfx::win::DirectManipulationHelper>
       direct_manipulation_helper_;
 
   // The location where the user clicked on the caption. We cache this when we
   // receive the WM_NCLBUTTONDOWN message. We use this in the subsequent
   // WM_NCMOUSEMOVE message to see if the mouse actually moved.
   // Please refer to the HandleMouseEventInternal function for details on why
@@ skipping 27 matching lines @@
 
   // The factory used with BEGIN_SAFE_MSG_MAP_EX.
   base::WeakPtrFactory<HWNDMessageHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(HWNDMessageHandler);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIN_HWND_MESSAGE_HANDLER_H_