Add SkTHashSet::find()

src/core/SkTHash.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkTHash_DEFINED
 #define SkTHash_DEFINED
 
@@ skipping 213 matching lines @@
     // Clear the set.
     void reset() { fTable.reset(); }
 
     // How many items are in the set?
     int count() const { return fTable.count(); }
 
     // Copy an item into the set.
     void add(const T& item) { fTable.set(item); }
 
     // Is this item in the set?
-    bool contains(const T& item) const { return SkToBool(fTable.find(item)); }
+    bool contains(const T& item) const { return SkToBool(this->find(item)); }
+
+    // If an item equal to this is in the set, return a pointer to it, otherwise null.
+    // This pointer remains valid until the next call to add().
+    const T* find(const T& item) const { return fTable.find(item); }
 
 private:
     struct Traits {
         static const T& GetKey(const T& item) { return item; }
         static uint32_t Hash(const T& item) { return HashT(item); }
     };
     SkTHashTable<T, T, Traits> fTable;
 };
 
 #endif//SkTHash_DEFINED