Move functions from SkGr to SkGrPriv.h

Review URL: https://codereview.chromium.org/1397123002
diff --git a/src/gpu/SkGr.cpp b/src/gpu/SkGr.cpp
index cff6172..8f9555a 100644
--- a/src/gpu/SkGr.cpp
+++ b/src/gpu/SkGr.cpp
@@ -10,6 +10,7 @@
 #include "SkGr.h"
 
 #include "GrCaps.h"
+#include "GrContext.h"
 #include "GrDrawContext.h"
 #include "GrXferProcessor.h"
 #include "GrYUVProvider.h"