VR: Split off UI code into a library to ease future unit testing.

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

Index: chrome/browser/android/vr_shell/ui_elements/ui_element.h
diff --git a/chrome/browser/android/vr_shell/ui_elements/ui_element.h b/chrome/browser/android/vr_shell/ui_elements/ui_element.h
index 4ee49ae99cb5e733f0c3e9dea725029bf7167e43..1cdeac7b1f5b5731818e84d52ea63e2e27b19ab9 100644
--- a/chrome/browser/android/vr_shell/ui_elements/ui_element.h
+++ b/chrome/browser/android/vr_shell/ui_elements/ui_element.h
@@ -22,7 +22,7 @@ class TimeTicks;
 namespace vr_shell {
 
 class Animation;
-class VrShellRenderer;
+class UiElementRenderer;
 
 enum XAnchoring {
   XNONE = 0,
@@ -107,7 +107,7 @@ class UiElement : public WorldRectangle {
   // Indicates whether the element should be tested for cursor input.
   bool IsHitTestable() const;
 
-  virtual void Render(VrShellRenderer* renderer,
+  virtual void Render(UiElementRenderer* renderer,
                       vr::Mat4f view_proj_matrix) const;
 
   virtual void Initialize();