Make GrClip.h private

BUG=skia:

Change-Id: I4aa3c2707811ece3a63d161035e316c3bbc1cd15
Reviewed-on: https://skia-review.googlesource.com/9482
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
diff --git a/tests/ProcessorTest.cpp b/tests/ProcessorTest.cpp
index 0b8f6fe..03646e1 100644
--- a/tests/ProcessorTest.cpp
+++ b/tests/ProcessorTest.cpp
@@ -9,6 +9,7 @@
 #include "Test.h"
 
 #if SK_SUPPORT_GPU
+#include "GrClip.h"
 #include "GrContext.h"
 #include "GrGpuResource.h"
 #include "GrPipelineBuilder.h"