Views: Extract text selection code from Textfield.

ui/views/selection_controller_delegate.h

+// Copyright 2016 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_SELECTION_CONTROLLER_DELEGATE_H_
+#define UI_VIEWS_SELECTION_CONTROLLER_DELEGATE_H_
+
+#include "ui/views/views_export.h"
+
+namespace ui {
+class MouseEvent;
+}
+
+namespace views {
+
+// An interface implemented/managed by a view which uses the
+// SelectionController.
+class VIEWS_EXPORT SelectionControllerDelegate {
+ public:
+  // Returns the associated RenderText instance to be used for selection.
+  virtual gfx::RenderText* GetRenderTextForSelectionController() = 0;
+
+  // Methods related to properties of the associated view.
+
+  // Returns true if the associated text view is read only.
+  virtual bool IsReadOnly() const = 0;
+  // Returns whether there is a drag operation originating from the associated
+  // view.
+  virtual bool HasTextBeingDragged() const = 0;
+  // Sets whether text is being dragged from the associated view.
+  virtual void SetTextBeingDragged(bool value) = 0;
+  // Returns the height of the associated view.
+  virtual int GetViewHeight() const = 0;
+  // Returns the width of the associated view.
+  virtual int GetViewWidth() const = 0;
+  // Returns the drag selection timer delay. This is the duration after which a
+  // drag selection is updated when the event location is outside the text
+  // bounds.
+  virtual int GetDragSelectionDelay() const = 0;
+
+  // Methods called to notify a mouse action which may change the associated
+  // view's text and/or selection.
+
+  // Called before performing a mouse action. Should not be called in succession
+  // and must always be followed by an OnAfterMouseAction call.
+  virtual void OnBeforeMouseAction() = 0;
+  // Called after the mouse action is performed. |text_changed| and
+  // |selection_changed| can be used by subclasses to make any necessary updates
+  // like redraw the text. Must always be preceeded by a OnBeforeMouseAction
+  // call.
+  virtual void OnAfterMouseAction(bool text_changed,
+                                  bool selection_changed) = 0;
+
+  // Called to notify when the current selection is updated. Must always be
+  // called during a mouse action.
+
+  // Called before the selection is updated. Not called in succession and always

[msw, 2016/10/18 23:15:05]

nit: normalize phrases here and below with those above:
  'Should not be called' vs 'Not called'
  'must always be followed by' vs 'always followed by'

[karandeepb, 2016/10/20 04:12:57]

Obsolete.

+  // followed by an OnAfterSelectionUpdated call.
+  virtual void OnBeforeSelectionUpdated() = 0;
+  // Called after the selection is updated. Not called in succession and always
+  // preceeded by an OnBeforeSelectionUpdated call.
+  virtual void OnAfterSelectionUpdated() = 0;
+
+  // Selection clipboard related methods. Called only when a mouse action is in
+  // progress.
+
+  // Moves the cursor to the event location and pastes the text from the
+  // selection clipboard. The view may also request focus. NO-OP if the
+  // associated text view is read-only or the event is not a middle click.
+  virtual void PasteSelectionClipboard(const ui::MouseEvent& event) = 0;
+  // Updates the selection clipboard with the currently selected text. Should
+  // empty the selection clipboard if no text is currently selected. NO-OP if
+  // the associated text view is obscured.
+  virtual void UpdateSelectionClipboard() = 0;
+
+ protected:
+  virtual ~SelectionControllerDelegate() {}
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_SELECTION_CONTROLLER_DELEGATE_H_