VR Shell: Allow UI elements to determine hit testing.

chrome/browser/android/vr_shell/ui_elements/ui_element.cc

 // 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.
 
 #include "chrome/browser/android/vr_shell/ui_elements/ui_element.h"
 
 #include <limits>
 
 #include "base/logging.h"
 #include "base/time/time.h"
@@ skipping 98 matching lines @@
 
 UiElement::~UiElement() = default;
 
 void UiElement::Render(VrShellRenderer* renderer,
                        vr::Mat4f view_proj_matrix) const {
   NOTREACHED();
 }
 
 void UiElement::Initialize() {}
 
-void UiElement::OnHoverEnter(gfx::PointF position) {}
+void UiElement::OnHoverEnter(const gfx::PointF& position) {}
 
 void UiElement::OnHoverLeave() {}
 
-void UiElement::OnMove(gfx::PointF position) {}
+void UiElement::OnMove(const gfx::PointF& position) {}
 
-void UiElement::OnButtonDown(gfx::PointF position) {}
+void UiElement::OnButtonDown(const gfx::PointF& position) {}
 
-void UiElement::OnButtonUp(gfx::PointF position) {}
+void UiElement::OnButtonUp(const gfx::PointF& position) {}
 
 void UiElement::OnBeginFrame(const base::TimeTicks& begin_frame_time) {}
 
 void UiElement::Animate(const base::TimeTicks& time) {
   for (auto& it : animations_) {
     Animation& animation = *it;
     if (time < animation.start)
       continue;
 
     // If |from| is not specified, start at the current values.
@@ skipping 81 matching lines @@
 }
 
 bool UiElement::IsHitTestable() const {
   return IsVisible() && hit_testable_;
 }
 
 void UiElement::SetEnabled(bool enabled) {
   visible_ = enabled;
 }
 
+bool UiElement::HitTest(const gfx::PointF& point) const {
+  return point.x() >= 0.0f && point.x() <= 1.0f && point.y() >= 0.0f &&
+         point.y() <= 1.0f;
+}
+
 }  // namespace vr_shell