Modify GrClipMaskManager to reflect logical constness

include/gpu/GrProcessorDataManager.h

Index: include/gpu/GrProcessorDataManager.h
diff --git a/include/gpu/GrProcessorDataManager.h b/include/gpu/GrProcessorDataManager.h
index a58cb4ef5136e201544e1a754fbcff1fdd66f6ad..ccc77d74ebdec188f21036e10349c568a56997f8 100644
--- a/include/gpu/GrProcessorDataManager.h
+++ b/include/gpu/GrProcessorDataManager.h
@@ -30,6 +30,11 @@ public:
     }
 
 private:
+    uint32_t currentSaveMarker() const { return 0; }
+    void restoreToSaveMarker(/*uint32_t marker*/) {}
+
+    // For GrPipelineBuilder::AutoRestoreProcessorDataManager
+    friend class GrPipelineBuilder;
     static const uint32_t kNumProcessor = 1;
     static const uint32_t kDataIndicesPerProcessor = 1;
     static const uint32_t kPreAllocDataPerProcessor = 1;