Update toast behavior and apperance according to UX requirement

chrome/browser/android/vr_shell/ui_elements/simple_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_SIMPLE_TEXTURED_ELEMENT_H_
 #define CHROME_BROWSER_ANDROID_VR_SHELL_UI_ELEMENTS_SIMPLE_TEXTURED_ELEMENT_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 12 matching lines @@
 class SimpleTexturedElement : public TexturedElement {
  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 SimpleTexturedElement(int maximum_width)
       : TexturedElement(maximum_width), texture_(base::MakeUnique<T>()) {}
   ~SimpleTexturedElement() override {}
   T* GetDerivedTexture() { return texture_.get(); }
 
+ protected:
+  UiTexture* GetTexture() const override { return texture_.get(); }
+
  private:
-  UiTexture* GetTexture() const override { return texture_.get(); }
   std::unique_ptr<T> texture_;
 
   DISALLOW_COPY_AND_ASSIGN(SimpleTexturedElement);
 };
 
 typedef SimpleTexturedElement<ExitWarningTexture> ExitWarning;
 typedef SimpleTexturedElement<InsecureContentPermanentTexture>
     PermanentSecurityWarning;
 typedef SimpleTexturedElement<InsecureContentTransientTexture>
     TransientSecurityWarning;
-typedef SimpleTexturedElement<ExclusiveScreenToastTexture> ExclusiveScreenToast;
 typedef SimpleTexturedElement<SplashScreenIconTexture> SplashScreenIcon;
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_UI_ELEMENTS_SIMPLE_TEXTURED_ELEMENT_H_