Fixes 1 pixel shift of text rendering on CrOS and Linux.

ui/gfx/render_text.cc

 // Copyright (c) 2012 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.h"
 
 #include <algorithm>
 #include <climits>
 
 #include "base/i18n/break_iterator.h"
@@ skipping 44 matching lines @@
   const int display_height = display_rect.height();
   const int font_height = font_list.GetHeight();
   // Lower and upper bound of baseline shift as we try to show as much area of
   // text as possible.  In particular case of |display_height| == |font_height|,
   // we do not want to shift the baseline.
   const int min_shift = std::min(0, display_height - font_height);
   const int max_shift = std::abs(display_height - font_height);
   const int baseline = font_list.GetBaseline();
   const int cap_height = font_list.GetCapHeight();
   const int internal_leading = baseline - cap_height;
-  const int baseline_shift =
-      (display_height - cap_height) / 2 - internal_leading;
+  // Some platforms don't support getting the cap height, and simply return

[msw, 2013/11/11 18:07:26]

This and your prior CL (http://crrev.com/59873002) both restore text height
centering instead of cap height centering for Pango. Doesn't that effectively
undo this part of you original CL:
https://codereview.chromium.org/25039002/diff/1099001/ui/gfx/platform_font_pa...
Should you undo the changes in these two latest CLs and that small part of the
original CL to keep the same behavior? Or do some fonts (on other platforms?)
actually not provide an internal_leading, and these coordinated workarounds
actually support some additional cases?

+  // the entire font ascent from GetCapHeight().  Centering the ascent makes
+  // the font look too low, so if GetCapHeight() returns the ascent, center
+  // the entire font height instead.
+  const int space =
+      display_height - ((internal_leading != 0) ? cap_height : font_height);
+  const int baseline_shift = space / 2 - internal_leading;
   return baseline + std::max(min_shift, std::min(max_shift, baseline_shift));
 }
 
 // Converts |gfx::Font::FontStyle| flags to |SkTypeface::Style| flags.
 SkTypeface::Style ConvertFontStyleToSkiaTypefaceStyle(int font_style) {
   int skia_style = SkTypeface::kNormal;
   skia_style |= (font_style & gfx::Font::BOLD) ? SkTypeface::kBold : 0;
   skia_style |= (font_style & gfx::Font::ITALIC) ? SkTypeface::kItalic : 0;
   return static_cast<SkTypeface::Style>(skia_style);
 }
@@ skipping 1076 matching lines @@
   cursor_bounds_ += delta_offset;
 }
 
 void RenderText::DrawSelection(Canvas* canvas) {
   const std::vector<Rect> sel = GetSubstringBounds(selection());
   for (std::vector<Rect>::const_iterator i = sel.begin(); i < sel.end(); ++i)
     canvas->FillRect(*i, selection_background_focused_color_);
 }
 
 }  // namespace gfx