Make fID and MixedID calculations private

src/gpu/GrBitmapTextContext.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrBitmapTextContext.h"
 #include "GrAtlas.h"
 #include "GrDefaultGeoProcFactory.h"
@@ skipping 120 matching lines @@
     fTotalVertexCount = kVerticesPerGlyph*numGlyphs;
 
     const char* stop = text + byteLength;
 
     SkAutoKern autokern;
 
     SkFixed fxMask = ~0;
     SkFixed fyMask = ~0;
     SkFixed halfSampleX, halfSampleY;
     if (cache->isSubpixel()) {
-        halfSampleX = halfSampleY = (SK_FixedHalf >> SkGlyph::kSubBits);
+        halfSampleX = halfSampleY = SkGlyph::kSubpixelRound;
         SkAxisAlignment baseline = SkComputeAxisAlignmentForHText(viewMatrix);
         if (kX_SkAxisAlignment == baseline) {
             fyMask = 0;
             halfSampleY = SK_FixedHalf;
         } else if (kY_SkAxisAlignment == baseline) {
             fxMask = 0;
             halfSampleX = SK_FixedHalf;
         }
     } else {
         halfSampleX = halfSampleY = SK_FixedHalf;
@@ skipping 445 matching lines @@
     }
 }
 
 inline void GrBitmapTextContext::finish() {
     this->flush();
     fTotalVertexCount = 0;
 
     GrTextContext::finish();
 }