VR: Add initial URL bar element and texture.

chrome/browser/android/vr_shell/textures/ui_texture.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_TEXTURES_UI_TEXTURE_H_
 #define CHROME_BROWSER_ANDROID_VR_SHELL_TEXTURES_UI_TEXTURE_H_
 
 #include <memory>
 
 #include "base/strings/string16.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/geometry/size_f.h"
 
 class SkCanvas;
 
 namespace gfx {
-class Canvas;
 class FontList;
 }  // namespace gfx
 
 namespace vr_shell {
 
 class UiTexture {
  public:
   UiTexture();
   virtual ~UiTexture();
 
   void DrawAndLayout(SkCanvas* canvas, const gfx::Size& texture_size);
   virtual gfx::Size GetPreferredTextureSize(int maximum_width) const = 0;
   virtual gfx::SizeF GetDrawnSize() const = 0;
 
  protected:
-  virtual void Draw(gfx::Canvas* canvas, const gfx::Size& texture_size) = 0;
+  virtual void Draw(SkCanvas* canvas, const gfx::Size& texture_size) = 0;
 
   static bool IsRTL();
+  static gfx::FontList GetDefaultFontList(int size);
   static gfx::FontList GetFontList(int size, base::string16 text);
 };
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_TEXTURES_UI_TEXTURE_H_