Revert of Added a system caret used for accessibility on Windows.

ui/views/win/hwnd_message_handler.cc

Index: ui/views/win/hwnd_message_handler.cc
diff --git a/ui/views/win/hwnd_message_handler.cc b/ui/views/win/hwnd_message_handler.cc
index 5190e41832157dbb3fb8c68774d998394d61e181..01c372801fee23a42f890ab9f3afb54b7d5733d3 100644
--- a/ui/views/win/hwnd_message_handler.cc
+++ b/ui/views/win/hwnd_message_handler.cc
@@ -21,14 +21,8 @@
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
-#include "base/win/scoped_comptr.h"
 #include "base/win/scoped_gdi_object.h"
 #include "base/win/windows_version.h"
-#include "ui/accessibility/platform/ax_platform_node_win.h"
-#include "ui/accessibility/platform/ax_system_caret_win.h"
-#include "ui/base/ime/input_method.h"
-#include "ui/base/ime/text_input_client.h"
-#include "ui/base/ime/text_input_type.h"
 #include "ui/base/view_prop.h"
 #include "ui/base/win/internal_constants.h"
 #include "ui/base/win/lock_state.h"
@@ -368,8 +362,6 @@
       weak_factory_(this) {}
 
 HWNDMessageHandler::~HWNDMessageHandler() {
-  DCHECK(delegate_->GetHWNDMessageDelegateInputMethod());
-  delegate_->GetHWNDMessageDelegateInputMethod()->RemoveObserver(this);
   delegate_ = NULL;
   // Prevent calls back into this class via WNDPROC now that we've been
   // destroyed.
@@ -403,8 +395,6 @@
   prop_window_target_.reset(new ui::ViewProp(hwnd(),
                             ui::WindowEventTarget::kWin32InputEventTarget,
                             static_cast<ui::WindowEventTarget*>(this)));
-  DCHECK(delegate_->GetHWNDMessageDelegateInputMethod());
-  delegate_->GetHWNDMessageDelegateInputMethod()->AddObserver(this);
 
   // Direct Manipulation is enabled on Windows 10+. The CreateInstance function
   // returns NULL if Direct Manipulation is not available.
@@ -959,46 +949,6 @@
   return result;
 }
 
-void HWNDMessageHandler::OnTextInputTypeChanged(
-    const ui::TextInputClient* client) {
-  if (!client || client->GetTextInputType() == ui::TEXT_INPUT_TYPE_NONE) {
-    DestroyAXSystemCaret();
-    return;
-  }
-
-  OnCaretBoundsChanged(client);
-}
-
-void HWNDMessageHandler::OnFocus() {}
-
-void HWNDMessageHandler::OnBlur() {}
-
-void HWNDMessageHandler::OnCaretBoundsChanged(
-    const ui::TextInputClient* client) {
-  if (!client || client->GetTextInputType() == ui::TEXT_INPUT_TYPE_NONE)
-    return;
-
-  if (!ax_system_caret_)
-    ax_system_caret_ = std::make_unique<ui::AXSystemCaretWin>(hwnd());
-
-  const gfx::Rect dip_caret_bounds(client->GetCaretBounds());
-  gfx::Rect caret_bounds =
-      display::win::ScreenWin::DIPToScreenRect(hwnd(), dip_caret_bounds);
-  // Collapse any selection.
-  caret_bounds.set_width(1);
-  ax_system_caret_->MoveCaretTo(caret_bounds);
-}
-
-void HWNDMessageHandler::OnTextInputStateChanged(
-    const ui::TextInputClient* client) {}
-
-void HWNDMessageHandler::OnInputMethodDestroyed(
-    const ui::InputMethod* input_method) {
-  DestroyAXSystemCaret();
-}
-
-void HWNDMessageHandler::OnShowImeIfNeeded() {}
-
 LRESULT HWNDMessageHandler::HandleMouseMessage(unsigned int message,
                                                WPARAM w_param,
                                                LPARAM l_param,
@@ -1583,14 +1533,10 @@
     // Retrieve MSAA dispatch object for the root view.
     base::win::ScopedComPtr<IAccessible> root(
         delegate_->GetNativeViewAccessible());
+
+    // Create a reference that MSAA will marshall to the client.
     reference_result = LresultFromObject(IID_IAccessible, w_param,
         static_cast<IAccessible*>(root.Detach()));
-  } else if (::GetFocus() == hwnd() && ax_system_caret_ &&
-             static_cast<DWORD>(OBJID_CARET) == obj_id) {
-    base::win::ScopedComPtr<IAccessible> ax_system_caret_accessible =
-        ax_system_caret_->GetCaret();
-    reference_result = LresultFromObject(IID_IAccessible, w_param,
-                                         ax_system_caret_accessible.Detach());
   }
 
   return reference_result;
@@ -2234,7 +2180,6 @@
         (notification_code & sc_mask) == SC_MAXIMIZE ||
         (notification_code & sc_mask) == SC_RESTORE) {
       delegate_->ResetWindowControls();
-      DestroyAXSystemCaret();
     } else if ((notification_code & sc_mask) == SC_MOVE ||
                (notification_code & sc_mask) == SC_SIZE) {
       if (!IsVisible()) {
@@ -2243,7 +2188,6 @@
         SetWindowLong(hwnd(), GWL_STYLE,
                       GetWindowLong(hwnd(), GWL_STYLE) | WS_VISIBLE);
       }
-      DestroyAXSystemCaret();
     }
   }
 
@@ -3058,8 +3002,4 @@
   SetBoundsInternal(shrunk_rect, false);
 }
 
-void HWNDMessageHandler::DestroyAXSystemCaret() {
-  ax_system_caret_ = nullptr;
-}
-
 }  // namespace views