For DirectWrite font metrics use the average character width from the TEXTMETRIC structure.

ui/gfx/platform_font_win.cc

Index: ui/gfx/platform_font_win.cc
diff --git a/ui/gfx/platform_font_win.cc b/ui/gfx/platform_font_win.cc
index f2b809b84b93952d6e662cb368d59142b6c18f00..8d8702edabc7d8f0f2b38695cf047be7455e95bf 100644
--- a/ui/gfx/platform_font_win.cc
+++ b/ui/gfx/platform_font_win.cc
@@ -509,11 +509,11 @@ PlatformFontWin::HFontRef* PlatformFontWin::CreateHFontRefFromSkia(
 
   // The metrics retrieved from skia don't have the average character width. In
   // any case if we get the average character width from skia then use that or
-  // use the text extent technique as documented by microsoft. See
-  // GetAverageCharWidthInDialogUnits for details.
+  // the average character width in the TEXTMETRIC structure.
+  // TODO(ananta): Investigate whether it is possible to retrieve this value
+  // from DirectWrite.
   const int ave_char_width =
-      skia_metrics.fAvgCharWidth == 0 ?
-          HFontRef::GetAverageCharWidthInDialogUnits(gdi_font)
+      skia_metrics.fAvgCharWidth == 0 ? font_metrics.tmAveCharWidth
               : skia_metrics.fAvgCharWidth;
 
   int style = 0;