VR: Route hover and click events to UI elements.

chrome/browser/android/vr_shell/ui_elements/ui_element.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 CHROME_BROWSER_ANDROID_VR_SHELL_UI_ELEMENTS_UI_ELEMENT_H_
 #define CHROME_BROWSER_ANDROID_VR_SHELL_UI_ELEMENTS_UI_ELEMENT_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 86 matching lines @@
   bool IsVisible() const;
 
   // Indicates whether the element should be tested for cursor input.
   bool IsHitTestable() const;
 
   virtual void Render(VrShellRenderer* renderer,
                       vr::Mat4f view_proj_matrix) const;
 
   virtual void Initialize();
 
+  // Controller interaction methods.
+  virtual void OnMouseEnter();

[cjgrant, 2017/04/26 14:36:16]

I used Mouse by convention, but these could be OnHoverEnter/OnHoverLeave, or
something else.  Thoughts?

[mthiesse, 2017/04/26 16:09:49]

Hover enter/leave sound better to me.

+  virtual void OnMouseLeave();
+  virtual void OnClick();
+
   // Valid IDs are non-negative.
   int id = -1;
 
   // Name string for debugging and testing purposes.
   std::string name;
 
   // If a non-negative parent ID is specified, applicable transformations
   // are applied relative to the parent, rather than absolutely.
   int parent_id = -1;
 
@@ skipping 53 matching lines @@
   // A flag usable during transformation calculates to avoid duplicate work.
   bool dirty;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(UiElement);
 };
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_UI_ELEMENTS_UI_ELEMENT_H_