Move distance field generation to the glyph cache

src/core/SkGlyph.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkGlyph_DEFINED
 #define SkGlyph_DEFINED
 
@@ skipping 11 matching lines @@
 
 struct SkGlyph {
     void*       fImage;
     SkPath*     fPath;
     SkFixed     fAdvanceX, fAdvanceY;
 
     uint32_t    fID;
     uint16_t    fWidth, fHeight;
     int16_t     fTop, fLeft;
 
+    void*       fDistanceField;
     uint8_t     fMaskFormat;
     int8_t      fRsbDelta, fLsbDelta;  // used by auto-kerning
 
     void init(uint32_t id) {
         fID             = id;
         fImage          = NULL;
         fPath           = NULL;
+        fDistanceField  = NULL;
         fMaskFormat     = MASK_FORMAT_UNKNOWN;
     }
 
     /**
      *  Compute the rowbytes for the specified width and mask-format.
      */
     static unsigned ComputeRowBytes(unsigned width, SkMask::Format format) {
         unsigned rb = width;
         if (SkMask::kBW_Format == format) {
             rb = (rb + 7) >> 3;
@@ skipping 92 matching lines @@
         y = FixedToSub(y);
         return (x << (kSubShift + kSubShiftX)) |
                (y << (kSubShift + kSubShiftY)) |
                code;
     }
 
     void toMask(SkMask* mask) const;
 };
 
 #endif