Reland: Implement Aura side of unified touch text selection for contents

ui/touch_selection/touch_handle_drawable_aura.h

+// Copyright 2015 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_TOUCH_SELECTION_TOUCH_HANDLE_DRAWABLE_AURA_H_
+#define UI_TOUCH_SELECTION_TOUCH_HANDLE_DRAWABLE_AURA_H_
+
+#include "ui/aura_extra/image_window_delegate.h"
+#include "ui/touch_selection/touch_handle.h"
+#include "ui/touch_selection/touch_handle_orientation.h"
+
+namespace ui {
+
+class TouchHandleDrawableAura : public TouchHandleDrawable,
+                                public aura_extra::ImageWindowDelegate {

[sadrul, 2015/03/05 12:37:03]

Instead of making TouchHandleDrawableAura a subclass of ImageWindowDelegate, can
TouchHandleDrawableAura have an instance of ImageWindowDelegate instead?
Something like:

  TouchHandleDrawableAura : TouchHandleDrawable {
    ImageWindowDelegate* window_delegate_;
    scoped_ptr<aura::Window> window_;
  }

As long as |window_| is alive, |window_delegate_| is guaranteed to be alive as
well, and so you can SetImage() etc. on it as you need to, and you don't need
the OnWindowDestroyed() override either.

[mohsen, 2015/03/06 23:10:08]

Yeah. Done.

+ public:
+  explicit TouchHandleDrawableAura(aura::Window* parent);
+  ~TouchHandleDrawableAura() override;
+
+  // Returns the maximum width/height that can be occupied by a handle image.
+  static gfx::Size GetMaxHandleImageSize();
+
+ protected:
+  // aura_extra::ImageWindowDelegate:
+  void OnWindowDestroyed(aura::Window* window) override;
+
+ private:
+  void UpdateBounds();
+
+  // TouchHandleDrawable:
+  void SetEnabled(bool enabled) override;
+  void SetOrientation(TouchHandleOrientation orientation) override;
+  void SetAlpha(float alpha) override;
+  void SetFocus(const gfx::PointF& position) override;
+  gfx::RectF GetVisibleBounds() const override;
+
+  scoped_ptr<aura::Window> window_;
+  bool enabled_;
+  float alpha_;
+  TouchHandleOrientation orientation_;
+
+  // Focal position of the handle set via SetFocus (normally located on the
+  // intersection of the cursor line and the text base line).
+  gfx::PointF focal_position_;
+
+  // Window bounds relative to the focal position.
+  gfx::RectF relative_bounds_;
+
+  DISALLOW_COPY_AND_ASSIGN(TouchHandleDrawableAura);
+};
+
+}  // namespace ui
+
+#endif  // UI_TOUCH_SELECTION_TOUCH_HANDLE_DRAWABLE_AURA_H_