VR Shell: Allow UI elements to determine hit testing.

chrome/browser/android/vr_shell/ui_elements/close_button.h

 // Copyright 2017 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 CHROME_BROWSER_ANDROID_VR_SHELL_UI_ELEMENTS_CLOSE_BUTTON_H_
 #define CHROME_BROWSER_ANDROID_VR_SHELL_UI_ELEMENTS_CLOSE_BUTTON_H_
 
 #include <memory>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "chrome/browser/android/vr_shell/ui_elements/textured_element.h"
 
 namespace vr_shell {
 
 class CloseButtonTexture;
 class UiTexture;
 
 class CloseButton : public TexturedElement {
  public:
   explicit CloseButton(base::Callback<void()> click_handler);
   ~CloseButton() override;
 
   void OnHoverLeave() override;
-  void OnHoverEnter(gfx::PointF position) override;
-  void OnButtonDown(gfx::PointF position) override;
-  void OnButtonUp(gfx::PointF position) override;
+  void OnHoverEnter(const gfx::PointF& position) override;
+  void OnMove(const gfx::PointF& position) override;
+  void OnButtonDown(const gfx::PointF& position) override;
+  void OnButtonUp(const gfx::PointF& position) override;
+  bool HitTest(const gfx::PointF& point) const override;
 
  private:
   UiTexture* GetTexture() const override;
-  void OnStateUpdated();
+  void OnStateUpdated(const gfx::PointF& position);
 
   std::unique_ptr<CloseButtonTexture> texture_;
   bool down_ = false;
-  bool hover_ = false;
   base::Callback<void()> click_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(CloseButton);
 };
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_UI_ELEMENTS_CLOSE_BUTTON_H_