Add support for glCompressedTexSubImage2D

R=bsalomon@google.com, robertphillips@google.com

Author: krajcevski@google.com

Review URL: https://codereview.chromium.org/329213002
diff --git a/src/gpu/gl/debug/GrGLCreateDebugInterface.cpp b/src/gpu/gl/debug/GrGLCreateDebugInterface.cpp
index 7c430b4..788179c 100644
--- a/src/gpu/gl/debug/GrGLCreateDebugInterface.cpp
+++ b/src/gpu/gl/debug/GrGLCreateDebugInterface.cpp
@@ -855,6 +855,7 @@
     functions->fColorMask = noOpGLColorMask;
     functions->fCompileShader = noOpGLCompileShader;
     functions->fCompressedTexImage2D = noOpGLCompressedTexImage2D;
+    functions->fCompressedTexSubImage2D = noOpGLCompressedTexSubImage2D;
     functions->fCopyTexSubImage2D = noOpGLCopyTexSubImage2D;
     functions->fCreateProgram = debugGLCreateProgram;
     functions->fCreateShader = debugGLCreateShader;