Mark Render{Frame,View}::GetWebkitPreferences() return values as const.

content/renderer/sad_plugin.h

Index: content/renderer/sad_plugin.h
diff --git a/content/renderer/sad_plugin.h b/content/renderer/sad_plugin.h
index 4148c0ae0863b9c7438eea2e6ee7432adcd40a3c..412e8cb22a74493c1e4d73945c7c79380179f2cb 100644
--- a/content/renderer/sad_plugin.h
+++ b/content/renderer/sad_plugin.h
@@ -16,7 +16,7 @@ class Rect;
 namespace content {
 
 // Paints the sad plugin to the given canvas for the given plugin bounds. This
-// is used by both the NPAPI and the PPAPI out-of-process plugin impls.
+// is used by PPAPI out-of-process plugin impls.
 void PaintSadPlugin(blink::WebCanvas* canvas,
                     const gfx::Rect& plugin_rect,
                     const SkBitmap& sad_plugin_bitmap);