Move GLSurfaceOSMesaX11 into it's own source file.

ui/gl/gl_surface_osmesa_x11.h

Index: ui/gl/gl_surface_osmesa_x11.h
diff --git a/ui/gl/gl_surface_osmesa_x11.h b/ui/gl/gl_surface_osmesa_x11.h
new file mode 100644
index 0000000000000000000000000000000000000000..4a12521060fbd46fc8fbebf28f34a6b3b5c94cec
--- /dev/null
+++ b/ui/gl/gl_surface_osmesa_x11.h
@@ -0,0 +1,52 @@
+// 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_SURFACE_OSMESA_X11_H_
+#define UI_GL_GL_SURFACE_OSMESA_X11_H_
+
+#include <X11/Xlib.h>
+
+#include "base/macros.h"
+#include "ui/gfx/native_widget_types.h"
+#include "ui/gl/gl_export.h"
+#include "ui/gl/gl_surface.h"
+#include "ui/gl/gl_surface_osmesa.h"
+
+namespace gl {
+
+// This OSMesa GL surface can use XLib to swap the contents of the buffer to a
+// view.
+class GL_EXPORT GLSurfaceOSMesaX11 : public GLSurfaceOSMesa {
+ public:
+  explicit GLSurfaceOSMesaX11(gfx::AcceleratedWidget window);
+
+  static bool InitializeOneOff();
+
+  // Implement a subset of GLSurface.
+  bool Initialize(GLSurface::Format format) override;
+  void Destroy() override;
+  bool Resize(const gfx::Size& new_size,
+              float scale_factor,
+              bool alpha) override;
+  bool IsOffscreen() override;
+  gfx::SwapResult SwapBuffers() override;
+  bool SupportsPostSubBuffer() override;
+  gfx::SwapResult PostSubBuffer(int x, int y, int width, int height) override;
+
+ protected:
+  ~GLSurfaceOSMesaX11() override;
+
+ private:
+  Display* xdisplay_;
+  GC window_graphics_context_;
+  gfx::AcceleratedWidget window_;
+  GC pixmap_graphics_context_;
+  Pixmap pixmap_;
+
+  DISALLOW_COPY_AND_ASSIGN(GLSurfaceOSMesaX11);
+};
+
+}  // namespace gl
+
+#endif  // UI_GL_GL_SURFACE_OSMESA_X11_H_