Generate param traits size methods for IPC files in content/ (and traits it depends on).

ui/gfx/ipc/skia/gfx_skia_param_traits.h

Index: ui/gfx/ipc/skia/gfx_skia_param_traits.h
diff --git a/ui/gfx/ipc/skia/gfx_skia_param_traits.h b/ui/gfx/ipc/skia/gfx_skia_param_traits.h
index d3acc9308656956fc96d0b363ce6344a5d423464..977470bf660dec69baa73c78d1643f5c6b1acec7 100644
--- a/ui/gfx/ipc/skia/gfx_skia_param_traits.h
+++ b/ui/gfx/ipc/skia/gfx_skia_param_traits.h
@@ -27,6 +27,7 @@ namespace IPC {
 template <>
 struct GFX_SKIA_IPC_EXPORT ParamTraits<SkBitmap> {
   using param_type = SkBitmap;
+  static void GetSize(base::PickleSizer* s, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,
@@ -37,6 +38,7 @@ struct GFX_SKIA_IPC_EXPORT ParamTraits<SkBitmap> {
 template <>
 struct GFX_SKIA_IPC_EXPORT ParamTraits<gfx::Transform> {
   using param_type = gfx::Transform;
+  static void GetSize(base::PickleSizer* s, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,