Make fID and MixedID calculations private

src/ports/SkScalerContext_win_dw.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkScalarContext_win_dw_DEFINED
 #define SkScalarContext_win_dw_DEFINED
 
 #include "SkScalar.h"
 #include "SkScalerContext.h"
 #include "SkTypeface_win_dw.h"
 #include "SkTypes.h"
 
 #include <dwrite.h>
 
-struct SkGlyph;
+class SkGlyph;
 class SkDescriptor;
 
 class SkScalerContext_DW : public SkScalerContext {
 public:
     SkScalerContext_DW(DWriteFontTypeface*, const SkDescriptor* desc);
     virtual ~SkScalerContext_DW();
 
 protected:
     unsigned generateGlyphCount() SK_OVERRIDE;
     uint16_t generateCharToGlyph(SkUnichar uni) SK_OVERRIDE;
@@ skipping 31 matching lines @@
     /** The text size to measure with. */
     SkScalar fTextSizeMeasure;
     SkAutoTUnref<DWriteFontTypeface> fTypeface;
     int fGlyphCount;
     DWRITE_RENDERING_MODE fRenderingMode;
     DWRITE_TEXTURE_TYPE fTextureType;
     DWRITE_MEASURING_MODE fMeasuringMode;
 };
 
 #endif