ui: Use skia::RefPtr<T> for implicit safe reference counting.

chrome/browser/ui/libgtk2ui/gtk2_ui.cc

Index: chrome/browser/ui/libgtk2ui/gtk2_ui.cc
diff --git a/chrome/browser/ui/libgtk2ui/gtk2_ui.cc b/chrome/browser/ui/libgtk2ui/gtk2_ui.cc
index 2886e462de182ad13ca8959acf92dc0840004c27..ea2fbef26e913afbc053ec04cf9b18b7c190fdc0 100644
--- a/chrome/browser/ui/libgtk2ui/gtk2_ui.cc
+++ b/chrome/browser/ui/libgtk2ui/gtk2_ui.cc
@@ -762,13 +762,12 @@ SkBitmap Gtk2UI::GenerateFrameImage(
         color_utils::HSLShift(base, kGtkFrameShift);
     if (gradient_top_color)
       gdk_color_free(gradient_top_color);
-    SkShader* shader = gfx::CreateGradientShader(
+    skia::RefPtr<SkShader> shader = gfx::CreateGradientShader(
         0, gradient_size, lighter, base);
     SkPaint paint;
     paint.setStyle(SkPaint::kFill_Style);
     paint.setAntiAlias(true);
-    paint.setShader(shader);
-    shader->unref();
+    paint.setShader(shader.get());
 
     canvas.DrawRect(gfx::Rect(0, 0, kToolbarImageWidth, gradient_size), paint);
   }