Make the debug interface a GrGLTestInterface subclass.

src/gpu/gl/debug/GrTextureUnitObj.h

Index: src/gpu/gl/debug/GrTextureUnitObj.h
diff --git a/src/gpu/gl/debug/GrTextureUnitObj.h b/src/gpu/gl/debug/GrTextureUnitObj.h
index b0254a0fc1a4d47d377a60c3c07a86532c8931ea..5c7a03980bde05ae3364fca4e5c0888a1edd08c5 100644
--- a/src/gpu/gl/debug/GrTextureUnitObj.h
+++ b/src/gpu/gl/debug/GrTextureUnitObj.h
@@ -14,7 +14,7 @@ class GrTextureObj;
 ////////////////////////////////////////////////////////////////////////////////
 // Although texture unit objects are allocated & deallocated like the other
 // GL emulation objects they are derived from GrFakeRefObj to provide some
-// uniformity in how the GrDebugGL class manages resources
+// uniformity in how the debug interface class manages resources
 class GrTextureUnitObj : public GrFakeRefObj {
     GR_DEFINE_CREATOR(GrTextureUnitObj);