SkRecord: infer return type for visit() and mutate().

src/core/SkRecordPattern.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 SkRecordPattern_DEFINED
 #define SkRecordPattern_DEFINED
 
@@ skipping 129 matching lines @@
     template <typename T> T* first()  { return fFirst.get();   }
     template <typename T> T* second() { return fRest.template first<T>();  }
     template <typename T> T* third()  { return fRest.template second<T>(); }
     template <typename T> T* fourth() { return fRest.template third<T>();  }
 
 private:
     // If first isn't a Greedy, try to match at i once.
     template <typename T>
     int matchFirst(T* first, SkRecord* record, int i) {
         if (i < record->count()) {
-            if (record->mutate<bool>(i, *first)) {
+            if (record->mutate(i, *first)) {
                 return i+1;
             }
         }
         return 0;
     }
 
     // If first is a Greedy, walk i until it doesn't match.
     template <typename T>
     int matchFirst(Greedy<T>* first, SkRecord* record, int i) {
         while (i < record->count()) {
-            if (!record->mutate<bool>(i, *first)) {
+            if (!record->mutate(i, *first)) {
                 return i;
             }
             i++;
         }
         return 0;
     }
 
     First            fFirst;
     Pattern<Rest...> fRest;
 };
 
 }  // namespace SkRecords
 
 #endif//SkRecordPattern_DEFINED