gpu: Add support for GLX_EXT_texture_from_pixmap extension.

third_party/khronos/GLES2/gl2ext.h

 #ifndef __gl2ext_h_
 #define __gl2ext_h_
 
 /* $Revision: 16619 $ on $Date:: 2012-01-18 10:00:14 -0800 #$ */
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /*
@@ skipping 2010 matching lines @@
 #ifdef GL_GLEXT_PROTOTYPES
 #define glBindUniformLocationCHROMIUM GLES2_GET_FUN(BindUniformLocationCHROMIUM)
 #if !defined(GLES2_USE_CPP_BINDINGS)
 GL_APICALL void GL_APIENTRY glBindUniformLocationCHROMIUM (GLuint program, GLint location, const GLchar* name);
 #endif
 #else
 typedef void (GL_APIENTRYP PFNGLBINDUNIFORMLOCATIONCHROMIUM) (GLuint program, GLint location, const GLchar* name);
 #endif
 #endif
 
+/* GL_CHROMIUM_texture_from_pixmap */
+/* Exposes the GLX-specfic glXBindTexImageEXT entry point as a
+ * Chromium extension in the cross-platform API. Binds the Pixmap with
+ * the given ID (an X11 Pixmap) to the texture bound to the given target.
+ */
+#ifndef GL_CHROMIUM_texture_from_pixmap
+#define GL_CHROMIUM_texture_from_pixmap 1
+#ifdef GL_GLEXT_PROTOTYPES
+#define glTexImagePixmap2DCHROMIUM GLES2_GET_FUN(TexImagePixmap2DCHROMIUM)
+#if !defined(GLES2_USE_CPP_BINDINGS)
+GL_APICALL void GL_APIENTRY glTexImagePixmap2DCHROMIUM (GLenum target, GLuint pixmapId);
+#endif
+#else
+typedef void (GL_APIENTRYP PFNGLTEXIMAGEPIXMAP2DCHROMIUM) (GLenum target, GLuint pixmapId);
+#endif
+#endif
+
 #ifdef __cplusplus
 }
 #endif
 
 #endif /* __gl2ext_h_ */