Move GLContext creation from //ui/gl to //ui/gl/init.

ui/gl/gl_context.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_GL_CONTEXT_H_
 #define UI_GL_GL_CONTEXT_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 180 matching lines @@
  protected:
   ~GLContextReal() override;
 
   void SetCurrent(GLSurface* surface) override;
 
  private:
   std::unique_ptr<GPUTiming> gpu_timing_;
   DISALLOW_COPY_AND_ASSIGN(GLContextReal);
 };
 
+// Wraps GLContext in scoped_refptr and tries to initializes it. Returns a
+// scoped_refptr containing the initialized GLContext or nullptr if
+// initialization fails.
+GL_EXPORT scoped_refptr<GLContext> InitializeGLContext(
+    scoped_refptr<GLContext> context,
+    GLSurface* compatible_surface,
+    GpuPreference gpu_preference);
+
 }  // namespace gl
 
 #endif  // UI_GL_GL_CONTEXT_H_