Fix clipping RenderTextHarfBuzz text on Windows 8.

ui/gfx/render_text_harfbuzz.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/render_text_harfbuzz.h"
 
 #include <limits>
 #include <map>
 
 #include "base/i18n/bidi_line_iterator.h"
@@ skipping 1188 matching lines @@
   run->positions.reset(new SkPoint[run->glyph_count]);
   run->width = 0.0f;
   for (size_t i = 0; i < run->glyph_count; ++i) {
     DCHECK_LE(infos[i].codepoint, std::numeric_limits<uint16>::max());
     run->glyphs[i] = static_cast<uint16>(infos[i].codepoint);
     run->glyph_to_char[i] = infos[i].cluster;
     const SkScalar x_offset = SkFixedToScalar(hb_positions[i].x_offset);
     const SkScalar y_offset = SkFixedToScalar(hb_positions[i].y_offset);
     run->positions[i].set(run->width + x_offset, -y_offset);
     run->width += SkFixedToScalar(hb_positions[i].x_advance);
-#if defined(OS_LINUX)
-    // Match Pango's glyph rounding logic on Linux.
+    // Round run widths if subpixel positioning is off to match native behavior.
     if (!run->render_params.subpixel_positioning)
       run->width = std::floor(run->width + 0.5f);
-#endif
   }
 
   hb_buffer_destroy(buffer);
   hb_font_destroy(harfbuzz_font);
   return true;
 }
 
 }  // namespace gfx