Implement OSMesa image transport for TOUCH_UI builds

ui/gfx/gl/gl_surface_glx.h

 // Copyright (c) 2011 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_GFX_GL_GL_SURFACE_GLX_H_
 #define UI_GFX_GL_GL_SURFACE_GLX_H_
 
 #include "ui/gfx/gl/gl_surface.h"
 
 #include "ui/base/x/x11_util.h"
@@ skipping 46 matching lines @@
   NativeViewGLSurfaceGLX();
 
   gfx::PluginWindowHandle window_;
 
  private:
   void* config_;
   DISALLOW_COPY_AND_ASSIGN(NativeViewGLSurfaceGLX);
 };
 
 // A surface used to render to an offscreen pbuffer.
-class PbufferGLSurfaceGLX : public GLSurfaceGLX {
+class GL_EXPORT PbufferGLSurfaceGLX : public GLSurfaceGLX {
  public:
   explicit PbufferGLSurfaceGLX(const gfx::Size& size);
   virtual ~PbufferGLSurfaceGLX();
 
   // Implement GLSurfaceGLX.
   virtual bool Initialize();
   virtual void Destroy();
   virtual bool IsOffscreen();
   virtual bool SwapBuffers();
   virtual gfx::Size GetSize();
   virtual void* GetHandle();
   virtual void* GetConfig();
 
  private:
   gfx::Size size_;
   void* config_;
   XID pbuffer_;
   DISALLOW_COPY_AND_ASSIGN(PbufferGLSurfaceGLX);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_GL_GL_SURFACE_GLX_H_