Optimize setting the font when drawing in RenderTextLinux.

ui/gfx/pango_util.h

 // Copyright (c) 2011 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.
 
 #ifndef UI_GFX_PANGO_UTIL_H_
 #define UI_GFX_PANGO_UTIL_H_
 #pragma once
 
 #include <cairo/cairo.h>
 #include <pango/pango.h>
@@ skipping 55 matching lines @@
                      int flags);
 
 // Draw an underline under the text using |cr|, which must already be
 // initialized with the correct source. |extra_edge_width| is added to the
 // outer edge of the line.
 void DrawPangoTextUnderline(cairo_t* cr,
                             gfx::PlatformFontPango* platform_font,
                             double extra_edge_width,
                             const Rect& text_rect);
 
+// Returns the size in pixels for the specified |pango_font|.
+size_t GetPangoFontSizeInPixels(PangoFontDescription* pango_font);
+
 }  // namespace gfx
 
 #endif  // UI_GFX_PANGO_UTIL_H_