cc: Add trace output for individual DisplayItems

cc/resources/transparency_display_item.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/resources/transparency_display_item.h"
 
+#include "base/strings/stringprintf.h"
+#include "base/trace_event/trace_event_argument.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkPaint.h"
 #include "third_party/skia/include/core/SkXfermode.h"
 #include "ui/gfx/skia_util.h"
 
 namespace cc {
 
 TransparencyDisplayItem::TransparencyDisplayItem(float opacity,
                                                  SkXfermode::Mode blend_mode)
     : opacity_(opacity), blend_mode_(blend_mode) {
@@ skipping 15 matching lines @@
 }
 
 int TransparencyDisplayItem::ApproximateOpCount() const {
   return 1;
 }
 
 size_t TransparencyDisplayItem::PictureMemoryUsage() const {
   return sizeof(float) + sizeof(SkXfermode::Mode);
 }
 
+void TransparencyDisplayItem::AsValueInto(
+    base::debug::TracedValue* array) const {
+  array->AppendString(
+      base::StringPrintf("TransparencyDisplayItem opacity: %f, blend_mode: %d",
+                         opacity_, blend_mode_));
+}
+
 EndTransparencyDisplayItem::EndTransparencyDisplayItem() {
 }
 
 EndTransparencyDisplayItem::~EndTransparencyDisplayItem() {
 }
 
 void EndTransparencyDisplayItem::Raster(SkCanvas* canvas,
                                         SkDrawPictureCallback* callback) const {
   canvas->restore();
 }
 
 bool EndTransparencyDisplayItem::IsSuitableForGpuRasterization() const {
   return true;
 }
 
 int EndTransparencyDisplayItem::ApproximateOpCount() const {
   return 0;
 }
 
 size_t EndTransparencyDisplayItem::PictureMemoryUsage() const {
   return 0;
 }
 
+void EndTransparencyDisplayItem::AsValueInto(
+    base::debug::TracedValue* array) const {
+  array->AppendString("EndTransparencyDisplayItem");
+}
+
 }  // namespace cc