VR: Add initial URL bar element and texture.

chrome/browser/android/vr_shell/ui_elements/textured_element.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_TEXTURED_ELEMENT_H_
 #define CHROME_BROWSER_ANDROID_VR_SHELL_UI_ELEMENTS_TEXTURED_ELEMENT_H_
 
 #include "base/macros.h"
 #include "chrome/browser/android/vr_shell/ui_elements/ui_element.h"
 #include "ui/gl/gl_bindings.h"
 
 class SkSurface;
 
 namespace vr_shell {
 
 class UiTexture;
 
 class TexturedElement : public UiElement {
  public:
   // |preferred_width| is the element's desired width in meters. Constraints
   // implied by the texture being rendered may or may not allow it to be
   // rendered exactly at the preferred width.
   explicit TexturedElement(int maximum_width);
   ~TexturedElement() override;
 
-  void Initialize() override;
+  void Initialize() final;
 
   // UiElement interface.
   void Render(VrShellRenderer* renderer,
-              vr::Mat4f view_proj_matrix) const override;
+              vr::Mat4f view_proj_matrix) const final;
 
  protected:
   virtual UiTexture* GetTexture() const = 0;
+  void Update();
 
  private:
   void Flush(SkSurface* surface);
 
   gfx::Size texture_size_;
   GLuint texture_handle_;
   int maximum_width_;
 
   DISALLOW_COPY_AND_ASSIGN(TexturedElement);
 };
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_UI_ELEMENTS_TEXTURED_ELEMENT_H_