Merge GrClipMaskManager into GrClipStackClip

TBR=bsalomon@google.com
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2196393007

Review-Url: https://codereview.chromium.org/2196393007
diff --git a/src/gpu/SkGpuDevice.h b/src/gpu/SkGpuDevice.h
index fbbcc4e..efb6744 100644
--- a/src/gpu/SkGpuDevice.h
+++ b/src/gpu/SkGpuDevice.h
@@ -15,6 +15,7 @@
 #include "SkPicture.h"
 #include "SkRegion.h"
 #include "SkSurface.h"
+#include "GrClipStackClip.h"
 #include "GrDrawContext.h"
 #include "GrContext.h"
 #include "GrSurfacePriv.h"