DirectWrite to not round already subpixel metrics.

src/ports/SkFontHost_win_dw.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkTypes.h"
 #undef GetGlyphIndices
 
@@ skipping 841 matching lines @@
         HRVM(fTypeface->fDWriteFontFace->GetDesignGlyphMetrics(&glyphId, 1, &gm),
              "Could not get design metrics.");
     }
 
     DWRITE_FONT_METRICS dwfm;
     fTypeface->fDWriteFontFace->GetMetrics(&dwfm);
     SkScalar advanceX = SkScalarMulDiv(fTextSizeMeasure,
                                        SkIntToScalar(gm.advanceWidth),
                                        SkIntToScalar(dwfm.designUnitsPerEm));
 
-    if (!this->isSubpixel()) {
-        advanceX = SkScalarRoundToScalar(advanceX);
-    }
-
     SkVector vecs[1] = { { advanceX, 0 } };
     if (DWRITE_MEASURING_MODE_GDI_CLASSIC == fMeasuringMode ||
         DWRITE_MEASURING_MODE_GDI_NATURAL == fMeasuringMode)
     {
         fG_inv.mapVectors(vecs, SK_ARRAY_COUNT(vecs));
     } else {
         fSkXform.mapVectors(vecs, SK_ARRAY_COUNT(vecs));
     }
 
     glyph->fAdvanceX = SkScalarToFixed(vecs[0].fX);
@@ skipping 1126 matching lines @@
 }
 
 #include "SkFontMgr_indirect.h"
 SkFontMgr* SkFontMgr_New_DirectWriteRenderer(SkRemotableFontMgr* proxy) {
     SkAutoTUnref<SkFontMgr> impl(SkFontMgr_New_DirectWrite());
     if (impl.get() == NULL) {
         return NULL;
     }
     return SkNEW_ARGS(SkFontMgr_Indirect, (impl.get(), proxy));
 }