Linux: Fix some GdkPixbuf leaks.

gfx/gtk_util.h

 // Copyright (c) 2009 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 GFX_GTK_UTIL_H_
 #define GFX_GTK_UTIL_H_
 
 #include <stdint.h>
 #include <vector>
 
@@ skipping 17 matching lines @@
 
 namespace gfx {
 
 class Rect;
 
 extern const GdkColor kGdkWhite;
 extern const GdkColor kGdkBlack;
 extern const GdkColor kGdkGreen;
 
 // Convert and copy a SkBitmap to a GdkPixbuf. NOTE: this uses BGRAToRGBA, so
-// it is an expensive operation.
+// it is an expensive operation.  The returned GdkPixbuf will have a refcount of
+// 1, and the caller is responsible for unrefing it when done.
 GdkPixbuf* GdkPixbufFromSkBitmap(const SkBitmap* bitmap);
 
 // Modify the given region by subtracting the given rectangles.
 void SubtractRectanglesFromRegion(GdkRegion* region,
                                   const std::vector<Rect>& cutouts);
 
 }  // namespace gfx
 
 namespace {
 // A helper class that will g_object_unref |p| when it goes out of scope.
 // This never adds a ref, it only unrefs.
 template <typename Type>
 struct GObjectUnrefer {
   void operator()(Type* ptr) const {
     if (ptr)
       g_object_unref(ptr);
   }
 };
 }  // namespace
 
 // It's not legal C++ to have a templatized typedefs, so we wrap it in a
 // struct.  When using this, you need to include ::Type.  E.g.,
 // ScopedGObject<GdkPixbufLoader>::Type loader(gdk_pixbuf_loader_new());
 template<class T>
 struct ScopedGObject {
   typedef scoped_ptr_malloc<T, GObjectUnrefer<T> > Type;
 };
 
 #endif  // GFX_GTK_UTIL_H_