Refactor context creation parameters into a struct.

ui/gl/gl_context_osmesa.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_OSMESA_H_
 #define UI_GL_GL_CONTEXT_OSMESA_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_export.h"
 
 typedef struct osmesa_context* OSMesaContext;
 
 namespace gl {
 
 class GLShareGroup;
 class GLSurface;
 
 // Encapsulates an OSMesa OpenGL context that uses software rendering.
 class GL_EXPORT GLContextOSMesa : public GLContextReal {
  public:
   explicit GLContextOSMesa(GLShareGroup* share_group);
 
   // Implement GLContext.
   bool Initialize(GLSurface* compatible_surface,
-                  GpuPreference gpu_preference) override;
+                  const GLContextAttribs& attribs) override;
   bool MakeCurrent(GLSurface* surface) override;
   void ReleaseCurrent(GLSurface* surface) override;
   bool IsCurrent(GLSurface* surface) override;
   void* GetHandle() override;
   void OnSetSwapInterval(int interval) override;
 
  protected:
   ~GLContextOSMesa() override;
 
  private:
   void Destroy();
 
   OSMesaContext context_;
   bool is_released_;
 
   DISALLOW_COPY_AND_ASSIGN(GLContextOSMesa);
 };
 
 }  // namespace gl
 
 #endif  // UI_GL_GL_CONTEXT_OSMESA_H_