X11: Use better visuals for OpenGL

ui/gl/gl_share_group_glx.h

+// Copyright 2016 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_SHARE_GROUP_GLX_H_
+#define UI_GL_GL_SHARE_GROUP_GLX_H_
+
+#include <map>
+
+#include "base/memory/weak_ptr.h"
+#include "ui/gl/gl_share_group.h"
+
+namespace gl {
+
+// A group of GL contexts that share an ID namespace.
+class GL_EXPORT GLShareGroupGLX : public GLShareGroup {

[piman, 2016/09/22 21:24:55]

Maybe we can avoid special-casing GLX here, by moving the map to GLShareGroup,
and introducing a GLSurface::GetCompatibilityKey(), which would return the
fbconfig id on GLX and 0 on other platforms (maybe visual id on EGL+X11), and
would be the key to the (unordered?) map.

+ public:
+  GLShareGroupGLX();
+
+  void SetSharedContext(GLSurface* compatible, GLContext* context) override;
+  GLContext* GetSharedContext(GLSurface* compatible) override;
+
+ private:
+  ~GLShareGroupGLX() override;
+
+  std::map<unsigned long, base::WeakPtr<GLContext>> shared_contexts_;
+
+  DISALLOW_COPY_AND_ASSIGN(GLShareGroupGLX);
+};
+
+}  // namespace gl
+
+#endif  // UI_GL_GL_SHARE_GROUP_GLX_H_