Add builders for tracing event's structural arguments

cc/quads/picture_draw_quad.cc

Index: cc/quads/picture_draw_quad.cc
diff --git a/cc/quads/picture_draw_quad.cc b/cc/quads/picture_draw_quad.cc
index cb1c2c1db4ab80907a24cb9dbbb97fff6bbcab4a..af120a41e3951c7a9eb99e599acc05a88029c2e7 100644
--- a/cc/quads/picture_draw_quad.cc
+++ b/cc/quads/picture_draw_quad.cc
@@ -4,6 +4,7 @@
 
 #include "cc/quads/picture_draw_quad.h"
 
+#include "base/debug/trace_event_argument.h"
 #include "base/values.h"
 #include "cc/base/math_util.h"
 #include "cc/resources/platform_color.h"
@@ -79,9 +80,11 @@ const PictureDrawQuad* PictureDrawQuad::MaterialCast(const DrawQuad* quad) {
   return static_cast<const PictureDrawQuad*>(quad);
 }
 
-void PictureDrawQuad::ExtendValue(base::DictionaryValue* value) const {
+void PictureDrawQuad::ExtendValue(base::debug::TracedValue* value) const {
   ContentDrawQuadBase::ExtendValue(value);
-  value->Set("content_rect", MathUtil::AsValue(content_rect).release());
+  value->BeginArray("content_rect");
+  MathUtil::AddToTracedValue(content_rect, value);
+  value->EndArray();
   value->SetDouble("contents_scale", contents_scale);
   value->SetInteger("texture_format", texture_format);
   // TODO(piman): picture_pile?