minor SkSL changes to avoid compiler errors in Chromium

src/sksl/ir/SkSLFieldAccess.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
  
 #ifndef SKSL_FIELDACCESS
 #define SKSL_FIELDACCESS
 
 #include "SkSLExpression.h"
 #include "SkSLUtil.h"
 
 namespace SkSL {
 
 /**
  * An expression which extracts a field from a struct, as in 'foo.bar'.
  */
 struct FieldAccess : public Expression {
     enum OwnerKind {
         kDefault_OwnerKind,
         // this field access is to a field of an anonymous interface block (and thus, the field name
         // is actually in global scope, so only the field name needs to be written in GLSL)
         kAnonymousInterfaceBlock_OwnerKind
     };
 
     FieldAccess(std::unique_ptr<Expression> base, int fieldIndex, 
                 OwnerKind ownerKind = kDefault_OwnerKind)
-    : INHERITED(base->fPosition, kFieldAccess_Kind, base->fType.fields()[fieldIndex].fType)
+    : INHERITED(base->fPosition, kFieldAccess_Kind, *base->fType.fields()[fieldIndex].fType)
     , fBase(std::move(base))
     , fFieldIndex(fieldIndex)
     , fOwnerKind(ownerKind) {}
 
     virtual std::string description() const override {
         return fBase->description() + "." + fBase->fType.fields()[fFieldIndex].fName;
     }
 
     const std::unique_ptr<Expression> fBase;
     const int fFieldIndex;
     const OwnerKind fOwnerKind;
 
     typedef Expression INHERITED;
 };
 
 } // namespace
 
 #endif