Add caps and GL API for buffer texture

include/gpu/gl/GrGLFunctions.h

Index: include/gpu/gl/GrGLFunctions.h
diff --git a/include/gpu/gl/GrGLFunctions.h b/include/gpu/gl/GrGLFunctions.h
index a6b9b9a62338949f6c7ff16b3bcba7b0b5ae38c4..fcd89e14060230969d41778b31c80afc951c71bc 100644
--- a/include/gpu/gl/GrGLFunctions.h
+++ b/include/gpu/gl/GrGLFunctions.h
@@ -144,6 +144,7 @@ typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLStencilMaskProc)(GrGLuint mask);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLStencilMaskSeparateProc)(GrGLenum face, GrGLuint mask);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLStencilOpProc)(GrGLenum fail, GrGLenum zfail, GrGLenum zpass);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLStencilOpSeparateProc)(GrGLenum face, GrGLenum fail, GrGLenum zfail, GrGLenum zpass);
+typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLTexBufferProc)(GrGLenum target, GrGLenum internalformat, GrGLuint buffer);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLTexImage2DProc)(GrGLenum target, GrGLint level, GrGLint internalformat, GrGLsizei width, GrGLsizei height, GrGLint border, GrGLenum format, GrGLenum type, const GrGLvoid* pixels);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLTexParameteriProc)(GrGLenum target, GrGLenum pname, GrGLint param);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLTexParameterivProc)(GrGLenum target, GrGLenum pname, const GrGLint* params);
@@ -338,6 +339,8 @@ typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLGetVertexArrayIntegeri_vProc)(GrGLuin
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLGetVertexArrayPointeri_vProc)(GrGLuint vaobj, GrGLuint index, GrGLenum pname, GrGLvoid **param);
 typedef GrGLvoid* (GR_GL_FUNCTION_TYPE* GrGLMapNamedBufferRangeProc)(GrGLuint buffer, GrGLintptr offset, GrGLsizeiptr length, GrGLbitfield access);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLFlushMappedNamedBufferRangeProc)(GrGLuint buffer, GrGLintptr offset, GrGLsizeiptr length);
+// OpenGL 3.1
+typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLTextureBufferProc)(GrGLuint texture, GrGLenum target, GrGLenum internalformat, GrGLuint buffer);
 
 /* KHR_debug */
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLDebugMessageControlProc)(GrGLenum source, GrGLenum type, GrGLenum severity, GrGLsizei count, const GrGLuint* ids, GrGLboolean enabled);