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

src/core/SkRecord.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkRecord.h"
 #include <algorithm>
 
 SkRecord::~SkRecord() {
     Destroyer destroyer;
     for (int i = 0; i < this->count(); i++) {
-        this->mutate<void>(i, destroyer);
+        this->mutate(i, destroyer);
     }
 }
 
 void SkRecord::grow() {
     SkASSERT(fCount == fReserved);
     SkASSERT(fReserved > 0);
     fReserved *= 2;
     fRecords.realloc(fReserved);
 }
 
 size_t SkRecord::bytesUsed() const {
     size_t bytes = fAlloc.approxBytesAllocated() + sizeof(SkRecord);
     // If fReserved <= kInlineRecords, we've already accounted for fRecords with sizeof(SkRecord).
     // When we go over that limit, they're allocated on the heap (and the inline space is wasted).
     if (fReserved > kInlineRecords) {
         bytes += fReserved * sizeof(Record);
     }
     return bytes;
 }
 
 void SkRecord::defrag() {
     // Remove all the NoOps, preserving the order of other ops, e.g.
     //      Save, ClipRect, NoOp, DrawRect, NoOp, NoOp, Restore
     //  ->  Save, ClipRect, DrawRect, Restore
     Record* noops = std::remove_if(fRecords.get(), fRecords.get() + fCount,
                                    [](Record op) { return op.type() == SkRecords::NoOp_Type; });
     fCount = noops - fRecords.get();
 }