VR Shell: Allow UI elements to determine hit testing.

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

Index: chrome/browser/android/vr_shell/ui_elements/ui_element.cc
diff --git a/chrome/browser/android/vr_shell/ui_elements/ui_element.cc b/chrome/browser/android/vr_shell/ui_elements/ui_element.cc
index 330416e9ba444bf95fd6f21c7a2db4d7fdd99ee3..d48861dc9d26ec7751525bcd71d25302f03b8238 100644
--- a/chrome/browser/android/vr_shell/ui_elements/ui_element.cc
+++ b/chrome/browser/android/vr_shell/ui_elements/ui_element.cc
@@ -116,15 +116,15 @@ void UiElement::Render(VrShellRenderer* renderer,
 
 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) {}
 
@@ -226,4 +226,9 @@ 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