Add support for GL_CHROMIUM_pixel_transfer_buffer_object.

gpu/command_buffer/cmd_buffer_functions.txt

 // Copyright (c) 2012 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.
 
 // This file is read by build_gles2_cmd_buffer.py to generate commands.
 
 GL_APICALL void         GL_APIENTRY glActiveTexture (GLenum texture);
 GL_APICALL void         GL_APIENTRY glAttachShader (GLidProgram program, GLidShader shader);
 GL_APICALL void         GL_APIENTRY glBindAttribLocation (GLidProgram program, GLuint index, const char* name);
 GL_APICALL void         GL_APIENTRY glBindBuffer (GLenumBufferTarget target, GLidBindBuffer buffer);
@@ skipping 155 matching lines @@
 GL_APICALL GLboolean    GL_APIENTRY glIsVertexArrayOES (GLidVertexArray array);
 GL_APICALL void         GL_APIENTRY glBindVertexArrayOES (GLidBindVertexArray array);
 
 // Non-GL commands.
 GL_APICALL void         GL_APIENTRY glSwapBuffers (void);
 GL_APICALL GLuint       GL_APIENTRY glGetMaxValueInBufferCHROMIUM (GLidBuffer buffer_id, GLsizei count, GLenumGetMaxIndexType type, GLuint offset);
 GL_APICALL void         GL_APIENTRY glGenSharedIdsCHROMIUM (GLuint namespace_id, GLuint id_offset, GLsizeiNotNegative n, GLuint* ids);
 GL_APICALL void         GL_APIENTRY glDeleteSharedIdsCHROMIUM (GLuint namespace_id, GLsizeiNotNegative n, const GLuint* ids);
 GL_APICALL void         GL_APIENTRY glRegisterSharedIdsCHROMIUM (GLuint namespace_id, GLsizeiNotNegative n, const GLuint* ids);
 GL_APICALL GLboolean    GL_APIENTRY glEnableFeatureCHROMIUM (const char* feature);
+GL_APICALL void*        GL_APIENTRY glMapBufferCHROMIUM (GLuint target, GLenum access);
+GL_APICALL GLboolean    GL_APIENTRY glUnmapBufferCHROMIUM (GLuint target);
+
 GL_APICALL void*        GL_APIENTRY glMapBufferSubDataCHROMIUM (GLuint target, GLintptrNotNegative offset, GLsizeiptr size, GLenum access);
 GL_APICALL void         GL_APIENTRY glUnmapBufferSubDataCHROMIUM (const void* mem);
 GL_APICALL void*        GL_APIENTRY glMapTexSubImage2DCHROMIUM (GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, GLenum access);
 GL_APICALL void         GL_APIENTRY glUnmapTexSubImage2DCHROMIUM (const void* mem);
 GL_APICALL void         GL_APIENTRY glResizeCHROMIUM (GLuint width, GLuint height);
 GL_APICALL const GLchar* GL_APIENTRY glGetRequestableExtensionsCHROMIUM (void);
 GL_APICALL void         GL_APIENTRY glRequestExtensionCHROMIUM (const char* extension);
 GL_APICALL void         GL_APIENTRY glRateLimitOffscreenContextCHROMIUM (void);
 GL_APICALL void         GL_APIENTRY glGetMultipleIntegervCHROMIUM (const GLenum* pnames, GLuint count, GLint* results, GLsizeiptr size);
 GL_APICALL void         GL_APIENTRY glGetProgramInfoCHROMIUM (GLidProgram program, GLsizeiNotNegative bufsize, GLsizei* size, void* info);
 GL_APICALL GLuint       GL_APIENTRY glCreateStreamTextureCHROMIUM (GLuint texture);
 GL_APICALL void         GL_APIENTRY glDestroyStreamTextureCHROMIUM (GLuint texture);
 GL_APICALL void         GL_APIENTRY glGetTranslatedShaderSourceANGLE (GLidShader shader, GLsizeiNotNegative bufsize, GLsizeiOptional* length, char* source);
 GL_APICALL void         GL_APIENTRY glPostSubBufferCHROMIUM (GLint x, GLint y, GLint width, GLint height);
 GL_APICALL void         GL_APIENTRY glTexImageIOSurface2DCHROMIUM (GLenumTextureBindTarget target, GLsizei width, GLsizei height, GLuint ioSurfaceId, GLuint plane);
 GL_APICALL void         GL_APIENTRY glCopyTextureCHROMIUM (GLenum target, GLenum source_id, GLenum dest_id, GLint level, GLintTextureInternalFormat internalformat);
 GL_APICALL void         GL_APIENTRY glDrawArraysInstancedANGLE (GLenumDrawMode mode, GLint first, GLsizei count, GLsizei primcount);
 GL_APICALL void         GL_APIENTRY glDrawElementsInstancedANGLE (GLenumDrawMode mode, GLsizei count, GLenumIndexType type, const void* indices, GLsizei primcount);
 GL_APICALL void         GL_APIENTRY glVertexAttribDivisorANGLE (GLuint index, GLuint divisor);
 GL_APICALL void         GL_APIENTRY glGenMailboxCHROMIUM (GLbyte* mailbox);
 GL_APICALL void         GL_APIENTRY glProduceTextureCHROMIUM (GLenumTextureTarget target, const GLbyte* mailbox);
 GL_APICALL void         GL_APIENTRY glConsumeTextureCHROMIUM (GLenumTextureTarget target, const GLbyte* mailbox);
 GL_APICALL void         GL_APIENTRY glBindUniformLocationCHROMIUM (GLidProgram program, GLint location, const char* name);
 GL_APICALL void         GL_APIENTRY glBindTexImage2DCHROMIUM (GLenumTextureBindTarget target, GLint imageId);
 GL_APICALL void         GL_APIENTRY glReleaseTexImage2DCHROMIUM (GLenumTextureBindTarget target, GLint imageId);
 GL_APICALL void         GL_APIENTRY glTraceBeginCHROMIUM (const char* name);
 GL_APICALL void         GL_APIENTRY glTraceEndCHROMIUM (void);