cc: Add trace output for individual DisplayItems

cc/resources/float_clip_display_item.cc

 // Copyright 2015 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/float_clip_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 "ui/gfx/skia_util.h"
 
 namespace cc {
 
 FloatClipDisplayItem::FloatClipDisplayItem(gfx::RectF clip_rect)
     : clip_rect_(clip_rect) {
 }
 
 FloatClipDisplayItem::~FloatClipDisplayItem() {
@@ skipping 10 matching lines @@
 }
 
 int FloatClipDisplayItem::ApproximateOpCount() const {
   return 1;
 }
 
 size_t FloatClipDisplayItem::PictureMemoryUsage() const {
   return sizeof(gfx::RectF);
 }
 
+void FloatClipDisplayItem::AsValueInto(base::debug::TracedValue* array) const {
+  array->AppendString(base::StringPrintf("FloatClipDisplayItem rect: [%s]",
+                                         clip_rect_.ToString().c_str()));
+}
+
 EndFloatClipDisplayItem::EndFloatClipDisplayItem() {
 }
 
 EndFloatClipDisplayItem::~EndFloatClipDisplayItem() {
 }
 
 void EndFloatClipDisplayItem::Raster(SkCanvas* canvas,
                                      SkDrawPictureCallback* callback) const {
   canvas->restore();
 }
 
 bool EndFloatClipDisplayItem::IsSuitableForGpuRasterization() const {
   return true;
 }
 
 int EndFloatClipDisplayItem::ApproximateOpCount() const {
   return 0;
 }
 
 size_t EndFloatClipDisplayItem::PictureMemoryUsage() const {
   return 0;
 }
 
+void EndFloatClipDisplayItem::AsValueInto(
+    base::debug::TracedValue* array) const {
+  array->AppendString("EndFloatClipDisplayItem");
+}
+
 }  // namespace cc