linux: Round font sizes when going from points to pixels.

Round point-based Pango font sizes to the nearest pixel.
Otherwise, we can end up with smaller UI fonts than GTK+ 2.0
apps in some cases.

This seems to be in line with what get_scaled_size() does in
Pango's pango/pangofc-fontmap.c, and gives me identically
sized text in Gimp 2.6.12 and Chrome when I set the
Gtk/FontName XSETTINGS property to "Arial 10".

Note that Chrome doesn't currently honor additional
fine-grained configuration performed via FontConfig, like
disabling antialiasing for fonts of a certain size. That'll
happen in a separate change.

BUG=375824

Review URL: https://codereview.chromium.org/377413002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282204 0039d316-1c4b-4281-b951-d872f2087c98

ui/gfx/pango_util.cc

@@ -230,17 +230,15 @@ void SetUpPangoLayout(
   pango_layout_set_font_description(layout, desc.get());
 }
 
-size_t GetPangoFontSizeInPixels(PangoFontDescription* pango_font) {
-  size_t size_in_pixels = pango_font_description_get_size(pango_font);
-  if (pango_font_description_get_size_is_absolute(pango_font)) {
-    // If the size is absolute, then it's in Pango units rather than points.
-    // There are PANGO_SCALE Pango units in a device unit (pixel).
-    size_in_pixels /= PANGO_SCALE;
-  } else {
-    // Otherwise, we need to convert from points.
-    size_in_pixels = size_in_pixels * GetPixelsInPoint() / PANGO_SCALE;
-  }
-  return size_in_pixels;
+int GetPangoFontSizeInPixels(PangoFontDescription* pango_font) {
+  // If the size is absolute, then it's in Pango units rather than points. There
+  // are PANGO_SCALE Pango units in a device unit (pixel).
+  if (pango_font_description_get_size_is_absolute(pango_font))
+    return pango_font_description_get_size(pango_font) / PANGO_SCALE;
+
+  // Otherwise, we need to convert from points.
+  return static_cast<int>(GetPixelsInPoint() *
+      pango_font_description_get_size(pango_font) / PANGO_SCALE + 0.5);
 }
 
 PangoFontMetrics* GetPangoFontMetrics(PangoFontDescription* desc) {

ui/gfx/pango_util.h

@@ -52,7 +52,7 @@ void SetUpPangoLayout(
     int flags);
 
 // Returns the size in pixels for the specified |pango_font|.
-size_t GetPangoFontSizeInPixels(PangoFontDescription* pango_font);
+int GetPangoFontSizeInPixels(PangoFontDescription* pango_font);
 
 // Retrieves the Pango metrics for a Pango font description. Caches the metrics
 // and never frees them. The metrics objects are relatively small and very