cc: Add trace output for individual DisplayItems

cc/resources/clip_path_display_item.h

Index: cc/resources/clip_path_display_item.h
diff --git a/cc/resources/clip_path_display_item.h b/cc/resources/clip_path_display_item.h
index 6144201e06ab4465f8adef30aebe96f738adedc4..b9fa01bf1f4b983fe76ff418ba115caef535b592 100644
--- a/cc/resources/clip_path_display_item.h
+++ b/cc/resources/clip_path_display_item.h
@@ -31,6 +31,7 @@ class CC_EXPORT ClipPathDisplayItem : public DisplayItem {
   bool IsSuitableForGpuRasterization() const override;
   int ApproximateOpCount() const override;
   size_t PictureMemoryUsage() const override;
+  void AsValueInto(base::debug::TracedValue* array) const override;
 
  protected:
   ClipPathDisplayItem(const SkPath& path, SkRegion::Op clip_op, bool antialias);
@@ -54,6 +55,7 @@ class CC_EXPORT EndClipPathDisplayItem : public DisplayItem {
   bool IsSuitableForGpuRasterization() const override;
   int ApproximateOpCount() const override;
   size_t PictureMemoryUsage() const override;
+  void AsValueInto(base::debug::TracedValue* array) const override;
 
  protected:
   EndClipPathDisplayItem();