Refactor GL bindings so there is no global GLApi or DriverGL.

ui/gl/gl_glx_api_implementation.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_GLX_API_IMPLEMENTATION_H_
 #define UI_GL_GL_GLX_API_IMPLEMENTATION_H_
 
 #include <vector>
 
 #include "base/compiler_specific.h"
@@ skipping 35 matching lines @@
   void InitializeWithCommandLine(DriverGLX* driver,
                                  base::CommandLine* command_line);
 
   const char* glXQueryExtensionsStringFn(Display* dpy, int screen) override;
  private:
 
   std::vector<std::string> disabled_exts_;
   std::string filtered_exts_;
 };
 
+// Logs debug information for every GLX call.
+class GL_EXPORT DebugGLXApi : public GLXApi {
+ public:
+  DebugGLXApi(GLXApi* glx_api);
+  ~DebugGLXApi() override;
+
+  // Include the auto-generated part of this class. We split this because
+  // it means we can easily edit the non-auto generated parts right here in
+  // this file instead of having to edit some template or the code generator.
+  #include "gl_bindings_api_autogen_glx.h"
+
+ private:
+  GLXApi* glx_api_;
+};
+
 // Inserts a TRACE for every GLX call.
 class GL_EXPORT TraceGLXApi : public GLXApi {
  public:
   TraceGLXApi(GLXApi* glx_api) : glx_api_(glx_api) { }
   ~TraceGLXApi() override;
 
   // Include the auto-generated part of this class. We split this because
   // it means we can easily edit the non-auto generated parts right here in
   // this file instead of having to edit some template or the code generator.
   #include "gl_bindings_api_autogen_glx.h"
 
  private:
   GLXApi* glx_api_;
 };
 
 }  // namespace gl
 
 #endif  // UI_GL_GL_GLX_API_IMPLEMENTATION_H_