Add TRACE_EVENT_IS_NEW_TRACE as a way to snapshot objects at start of recording

cc/resources/picture.cc

 // Copyright 2012 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/picture.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 
@@ skipping 207 matching lines @@
 
   clones_.clear();
   for (int i = 0; i < num_threads; i++) {
     scoped_refptr<Picture> clone = make_scoped_refptr(
         new Picture(skia::AdoptRef(new SkPicture(clones[i])),
                     layer_rect_,
                     opaque_rect_,
                     pixel_refs_));
     clones_.push_back(clone);
 
-    TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(TRACE_DISABLED_BY_DEFAULT("cc.debug"),
-      "cc::Picture", clone.get(), TracedPicture::AsTraceablePicture(clone));
+    clone->EmitTraceSnapshot();
   }
 }
 
 void Picture::Record(ContentLayerClient* painter,
                      const SkTileGridPicture::TileGridInfo& tile_grid_info,
                      RenderingStats* stats) {
   TRACE_EVENT2("cc", "Picture::Record",
                "width", layer_rect_.width(),
                "height", layer_rect_.height());
 
@@ skipping 26 matching lines @@
     stats->total_record_time += base::TimeTicks::Now() - begin_record_time;
     stats->total_pixels_recorded +=
         layer_rect_.width() * layer_rect_.height();
   }
 
   canvas->restore();
   picture_->endRecording();
 
   opaque_rect_ = gfx::ToEnclosedRect(opaque_layer_rect);
 
-    TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(TRACE_DISABLED_BY_DEFAULT("cc.debug"),
-      "cc::Picture", this, TracedPicture::AsTraceablePicture(this));
+  EmitTraceSnapshot();
 }
 
 void Picture::GatherPixelRefs(
     const SkTileGridPicture::TileGridInfo& tile_grid_info,
     RenderingStats* stats) {
   TRACE_EVENT2("cc", "Picture::GatherPixelRefs",
                "width", layer_rect_.width(),
                "height", layer_rect_.height());
 
   DCHECK(picture_);
@@ skipping 93 matching lines @@
   size_t serialized_size = stream.bytesWritten();
   scoped_ptr<char[]> serialized_picture(new char[serialized_size]);
   stream.copyTo(serialized_picture.get());
   std::string b64_picture;
   base::Base64Encode(std::string(serialized_picture.get(), serialized_size),
                      &b64_picture);
   res->SetString("skp64", b64_picture);
   return res.PassAs<base::Value>();
 }
 
+void Picture::DidBeginTracing() {

[enne (OOO), 2013/06/01 03:10:45]

I'm not sure this function really needs to exist.

+  EmitTraceSnapshot();
+}
+
 base::LazyInstance<Picture::PixelRefs>
     Picture::PixelRefIterator::empty_pixel_refs_;
 
 Picture::PixelRefIterator::PixelRefIterator()
     : picture_(NULL),
       current_pixel_refs_(empty_pixel_refs_.Pointer()),
       current_index_(0),
       min_point_(-1, -1),
       max_point_(-1, -1),
       current_x_(0),
@@ skipping 90 matching lines @@
   scoped_ptr<base::DictionaryValue> raster_data(new base::DictionaryValue());
   raster_data->Set("picture_id", TracedValue::CreateIDRef(this).release());
   raster_data->SetDouble("scale", scale);
   raster_data->SetDouble("rect_x", rect.x());
   raster_data->SetDouble("rect_y", rect.y());
   raster_data->SetDouble("rect_width", rect.width());
   raster_data->SetDouble("rect_height", rect.height());
   return TracedValue::FromValue(raster_data.release());
 }
 
+void Picture::EmitTraceSnapshot() {
+  TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(TRACE_DISABLED_BY_DEFAULT("cc.debug"),
+      "cc::Picture", this, TracedPicture::AsTraceablePicture(this));
+}
+
 }  // namespace cc