simple patch to always init SkTextBlob uniqueID

include/core/SkTextBlob.h

Index: include/core/SkTextBlob.h
diff --git a/include/core/SkTextBlob.h b/include/core/SkTextBlob.h
index 6970e6d5c78294b19787bddd32d984c069d5c7f8..d31ec5c760d01a31abe1cc58d3cb7c9a28b56ae1 100644
--- a/include/core/SkTextBlob.h
+++ b/include/core/SkTextBlob.h
@@ -30,7 +30,7 @@ public:
     /**
      *  Return a non-zero, unique value representing the text blob.
      */
-    uint32_t uniqueID() const;
+    uint32_t uniqueID() const { return fUniqueID; }
 
     /**
      *  Serialize to a buffer.
@@ -98,7 +98,7 @@ private:
 
     const int        fRunCount;
     const SkRect     fBounds;
-    mutable uint32_t fUniqueID;
+    const uint32_t fUniqueID;
 
     SkDEBUGCODE(size_t fStorageSize;)