Expose GpuMemoryBufferId through glGetImageivCHROMIUM.

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 258 matching lines @@
 GL_APICALL void         GL_APIENTRY glResizeCHROMIUM (GLuint width, GLuint height, GLfloat scale_factor, GLboolean alpha);
 GL_APICALL const GLchar* GL_APIENTRY glGetRequestableExtensionsCHROMIUM (void);
 GL_APICALL void         GL_APIENTRY glRequestExtensionCHROMIUM (const char* extension);
 GL_APICALL void         GL_APIENTRY glGetProgramInfoCHROMIUM (GLidProgram program, GLsizeiNotNegative bufsize, GLsizei* size, void* info);
 GL_APICALL void         GL_APIENTRY glGetUniformBlocksCHROMIUM (GLidProgram program, GLsizeiNotNegative bufsize, GLsizei* size, void* info);
 GL_APICALL void         GL_APIENTRY glGetTransformFeedbackVaryingsCHROMIUM (GLidProgram program, GLsizeiNotNegative bufsize, GLsizei* size, void* info);
 GL_APICALL void         GL_APIENTRY glGetUniformsES3CHROMIUM (GLidProgram program, GLsizeiNotNegative bufsize, GLsizei* size, void* info);
 GL_APICALL GLuint       GL_APIENTRY glCreateImageCHROMIUM (ClientBuffer buffer, GLsizei width, GLsizei height, GLenum internalformat);
 GL_APICALL void         GL_APIENTRY glDestroyImageCHROMIUM (GLuint image_id);
 GL_APICALL GLuint       GL_APIENTRY glCreateGpuMemoryBufferImageCHROMIUM (GLsizei width, GLsizei height, GLenum internalformat, GLenum usage);
+GL_APICALL GLint        GL_APIENTRY glGetImageivCHROMIUM (GLuint image_id, GLenum param);

[piman, 2016/05/26 21:16:07]

So, if we call it glGetImageivCHROMIUM, it should look like an "iv" function,
i.e. one that takes a GLint* (for the return value) - that's the most GL-y way,
and slightly more scalable because we can also have other variations for other
queries we might need (e.g. an "uiv" version to get a GLuint, or if we want to
return >1 values).

If we want to return a GLint instead (that's less consistent, only a couple of
API calls do that), it shouldn't be "iv", but then again glGetImageCHROMIUM
would be weird by itself. glGetImageInfoCHROMIUM maybe?

[erikchen, 2016/05/26 21:41:27]

Changed the signature to be:
void glGetImageivCHROMIUM(GLuint image_id, GLenum param, GLint* data);

 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 source_id, GLenum dest_id, GLintTextureInternalFormat internalformat, GLenumPixelType dest_type, GLboolean unpack_flip_y, GLboolean unpack_premultiply_alpha, GLboolean unpack_unmultiply_alpha);
 GL_APICALL void         GL_APIENTRY glCopySubTextureCHROMIUM (GLenum source_id, GLenum dest_id, GLint xoffset, GLint yoffset, GLint x, GLint y, GLsizei width, GLsizei height, GLboolean unpack_flip_y, GLboolean unpack_premultiply_alpha, GLboolean unpack_unmultiply_alpha);
 GL_APICALL void         GL_APIENTRY glCompressedCopyTextureCHROMIUM (GLenum source_id, GLenum dest_id);
 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);
@@ skipping 60 matching lines @@
 // Extension GL_CHROMIUM_screen_space_antialiasing
 GL_APICALL void GL_APIENTRY glApplyScreenSpaceAntialiasingCHROMIUM (void);
 
 // Extension EXT_blend_func_extended
 GL_APICALL void         GL_APIENTRY glBindFragDataLocationIndexedEXT (GLidProgram program, GLuint colorNumber, GLuint index, const char* name);
 GL_APICALL void         GL_APIENTRY glBindFragDataLocationEXT (GLidProgram program, GLuint colorNumber, const char* name);
 GL_APICALL GLint        GL_APIENTRY glGetFragDataIndexEXT (GLidProgram program, const char* name);
 
 // Extension CHROMIUM_stream_texture_matrix
 GL_APICALL void         GL_APIENTRY glUniformMatrix4fvStreamTextureMatrixCHROMIUM (GLintUniformLocation location, GLbooleanFalseOnly transpose, const GLfloat* default_value);