Split DirectCompositionSurfaceWin into two parts.

ui/gl/scoped_make_current.h

 // Copyright (c) 2012 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 UI_GL_SCOPED_MAKE_CURRENT_H_
 #define UI_GL_SCOPED_MAKE_CURRENT_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "base/optional.h"
 #include "ui/gl/gl_export.h"
 
 namespace gl {
 class GLContext;
 class GLSurface;
 }
 
 namespace ui {
 
 class GL_EXPORT ScopedMakeCurrent {
  public:
   ScopedMakeCurrent(gl::GLContext* context, gl::GLSurface* surface);
   ~ScopedMakeCurrent();
 
   bool Succeeded() const;
 
  private:
   scoped_refptr<gl::GLContext> previous_context_;
   scoped_refptr<gl::GLSurface> previous_surface_;
   scoped_refptr<gl::GLContext> context_;
   scoped_refptr<gl::GLSurface> surface_;
   bool succeeded_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedMakeCurrent);
 };
 
+// This class is used to make sure a specified surface isn't current, and upon
+// destruction it will make the surface current again if it had been before.
+class GL_EXPORT ScopedReleaseCurrent {
+ public:
+  explicit ScopedReleaseCurrent(gl::GLSurface* this_surface);
+
+  ~ScopedReleaseCurrent();
+
+ private:
+  base::Optional<ScopedMakeCurrent> make_current_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedReleaseCurrent);
+};
+
 }  // namespace ui
 
 #endif  // UI_GL_SCOPED_MAKE_CURRENT_H_