Add a ScopedPangoFontDescription helper class and use it.

ui/gfx/pango_util.h

 // 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.
 
 #ifndef UI_GFX_PANGO_UTIL_H_
 #define UI_GFX_PANGO_UTIL_H_
 #pragma once
 
 #include <cairo/cairo.h>
 #include <pango/pango.h>
 #include <string>
 
 #include "base/i18n/rtl.h"
+#include "base/logging.h"
 #include "base/string16.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/base/ui_export.h"
 
 typedef struct _PangoContext PangoContext;
 
 namespace gfx {
 
 class Font;
 class PlatformFontPango;
 class Rect;
 
 // Creates and returns a PangoContext. The caller owns the context.
 PangoContext* GetPangoContext();
 
 // Returns the resolution (DPI) used by pango. A negative values means the
 // resolution hasn't been set.
 double GetPangoResolution();
 
+// Utility class to ensure that PangoFontDescription is freed.
+class ScopedPangoFontDescription {
+ public:
+  explicit ScopedPangoFontDescription(PangoFontDescription* description)
+      : description_(description) {
+    DCHECK(description);
+  }
+
+  ~ScopedPangoFontDescription() {
+    pango_font_description_free(description_);
+  }
+
+  PangoFontDescription* get() { return description_; }
+
+ private:
+  PangoFontDescription* description_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedPangoFontDescription);
+};
+
 // Uses Pango to draw text onto |cr|. This is the public method for d
 void UI_EXPORT DrawTextOntoCairoSurface(cairo_t* cr,
                                         const string16& text,
                                         const gfx::Font& font,
                                         const gfx::Rect& bounds,
                                         const gfx::Rect& clip,
                                         SkColor text_color,
                                         int flags);
 
 // ----------------------------------------------------------------------------
@@ skipping 52 matching lines @@
 size_t 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
 // expensive to look up.
 PangoFontMetrics* GetPangoFontMetrics(PangoFontDescription* desc);
 
 }  // namespace gfx
 
 #endif  // UI_GFX_PANGO_UTIL_H_