gpu: Add a new extension CHROMIUM_deschedule.

gpu/command_buffer/cmd_buffer_functions.txt

Index: gpu/command_buffer/cmd_buffer_functions.txt
diff --git a/gpu/command_buffer/cmd_buffer_functions.txt b/gpu/command_buffer/cmd_buffer_functions.txt
index 45263c1fa0a4239fb49b1d7757426021b2c4de45..b14ca1be7e9d3c8c98b7e1b5c0f1d9e136cde275 100644
--- a/gpu/command_buffer/cmd_buffer_functions.txt
+++ b/gpu/command_buffer/cmd_buffer_functions.txt
@@ -277,6 +277,7 @@ GL_APICALL GLuint       GL_APIENTRY glCreateImageCHROMIUM (ClientBuffer buffer,
 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 void         GL_APIENTRY glGetImageivCHROMIUM (GLuint image_id, GLenum param, GLint* data);
+GL_APICALL void         GL_APIENTRY glDescheduleUntilFinishedCHROMIUM (void);
 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);