SkPath::fIsVolatile does not need to be mutable.

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4696

Change-Id: I48b438ab1d99033ab2a422fb28e976cdf9188365
Reviewed-on: https://skia-review.googlesource.com/4696
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>
diff --git a/include/core/SkPath.h b/include/core/SkPath.h
index 36dfdfe..486a993 100644
--- a/include/core/SkPath.h
+++ b/include/core/SkPath.h
@@ -1126,7 +1126,7 @@
     uint8_t                                            fFillType;
     mutable uint8_t                                    fConvexity;
     mutable SkAtomic<uint8_t, sk_memory_order_relaxed> fFirstDirection;// SkPathPriv::FirstDirection
-    mutable SkBool8                                    fIsVolatile;
+    SkBool8                                            fIsVolatile;
 
     /** Resets all fields other than fPathRef to their initial 'empty' values.
      *  Assumes the caller has already emptied fPathRef.