Minor modifications to GrProgramDesc.h.

BUG=skia:

Review URL: https://codereview.chromium.org/1100483003
diff --git a/src/gpu/gl/GrGLTexture.h b/src/gpu/gl/GrGLTexture.h
index 8188f74..de3cf3f 100644
--- a/src/gpu/gl/GrGLTexture.h
+++ b/src/gpu/gl/GrGLTexture.h
@@ -13,6 +13,7 @@
 #include "GrTexture.h"
 #include "GrGLUtil.h"
 
+class GrGLGpu;
 
 class GrGLTexture : public GrTexture {