Allow textures to be moved from one GL context group to another.

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 1964 matching lines @@
 
 /* GL_CHROMIUM_command_buffer_query */
 /* Exposes GL_CHROMIUM_command_buffer_query.
  */
 #ifndef GL_CHROMIUM_command_buffer_query
 #define GL_CHROMIUM_command_buffer_query 1
 // TODO(gman): Get official numbers for these constants.
 #define GL_COMMANDS_ISSUED_CHROMIUM 0x84F2
 #endif
 
+/* GL_CHROMIUM_copy_texture */

[Ken Russell (switch to Gerrit), 2012/04/26 01:10:53]

Should be GL_CHROMIUM_texture_mailbox. Also, the mailbox size needs to be
defined in this file somehow. Minimally something like "#define
GL_MAILBOX_SIZE_CHROMIUM 32".

+#ifndef GL_CHROMIUM_copy_texture
+#define GL_CHROMIUM_copy_texture 1
+#ifdef GL_GLEXT_PROTOTYPES
+#define glGenMailboxCHROMIUM GLES2_GET_FUN(GenMailboxCHROMIUM)
+#define glProduceTextureCHROMIUM GLES2_GET_FUN(ProduceTextureCHROMIUM)
+#define glConsumeTextureCHROMIUM GLES2_GET_FUN(ConsumeTextureCHROMIUM)
+#if !defined(GLES2_USE_CPP_BINDINGS)
+GL_APICALL void GL_APIENTRY glGenMailboxCHROMIUM (char* mailbox);
+GL_APICALL void GL_APIENTRY glProduceTextureCHROMIUM (GLenum target, const char* mailbox);
+GL_APICALL void GL_APIENTRY glConsumeTextureCHROMIUM (GLenum target, const  char* mailbox);
+#endif
+#else
+typedef void (GL_APIENTRYP PFNGLGENMAILBOXCHROMIUM) (char* mailbox);
+typedef void (GL_APIENTRYP PFNGLPRODUCETEXTURECHROMIUM) (GLenum target, const char* mailbox);
+typedef void (GL_APIENTRYP PFNGLCONSUMETEXTURECHROMIUM) (GLenum target, const  char* mailbox);
+#endif
+#endif
+
 #ifdef __cplusplus
 }
 #endif
 
 #endif /* __gl2ext_h_ */