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 OnMove(gfx::PointF position) override;
   void OnButtonDown(gfx::PointF position) override;
   void OnButtonUp(gfx::PointF position) override;
+  bool HitTest(gfx::PointF point) const override;

[cjgrant, 2017/05/15 16:55:09]

How are we going to handle elements that have two hover/clickable regions
internally?  Hopefully we won't have any for BBB, but if we did, maybe some of
the input code that was just refactored in vr_shell_gl.cc should live in a
helper class, that can be used recursively by vr_shell_gl.cc and individual
elements if needed.

That way, two hoverable/clickable buttons on (say the URL bar) would be
guaranteed to work the same as two hoverable/clickable UiElements.

Thoughts (other than "not in this CL!")?

[mthiesse, 2017/05/15 21:11:27]

Don't like it, and also "not in this CL". An element should handle it's own
internals, though if something happens to be re-usable then of course we should
reuse it. The main reason not to share code is in-element hit-testing is 2D, and
scene hit-testing is 3D.

 
  private:
   UiTexture* GetTexture() const override;
-  void OnStateUpdated();
+  void OnStateUpdated(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_