Add builders for tracing event's structural arguments

cc/resources/picture_pile_base.h

Index: cc/resources/picture_pile_base.h
diff --git a/cc/resources/picture_pile_base.h b/cc/resources/picture_pile_base.h
index f244f8fcf894face208fa1d8d449313e1e0cc3b5..b188df7d62f6f4b94b821f3ccffbd5346c6650d5 100644
--- a/cc/resources/picture_pile_base.h
+++ b/cc/resources/picture_pile_base.h
@@ -18,6 +18,9 @@
 #include "ui/gfx/size.h"
 
 namespace base {
+namespace debug {
+class TracedValue;
+}
 class Value;
 }
 
@@ -52,7 +55,7 @@ class CC_EXPORT PicturePileBase : public base::RefCounted<PicturePileBase> {
   void SetTileGridSize(const gfx::Size& tile_grid_size);
   TilingData& tiling() { return tiling_; }
 
-  scoped_ptr<base::Value> AsValue() const;
+  void AsValueInto(base::debug::TracedValue* array) const;
 
  protected:
   class CC_EXPORT PictureInfo {