Dump more information for layers/transform node

- cc::TransformNode::flattens_inherited_transform

- ccLayerId and ccContentsLayerId in GraphicsLayerAsJSON for matching
  blink and cc layers

TBR=chrishtr@chromium.org # for trivial change in cc

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I03ce50e44bca724a2d5b6b9a88ce38bc7d2d2835
Reviewed-on: https://chromium-review.googlesource.com/1225871
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#591410}

cc/trees/transform_node.cc

@@ -109,6 +109,8 @@ void TransformNode::AsValueInto(base::trace_event::TracedValue* value) const {
   MathUtil::AddToTracedValue("post_local", post_local, value);
   value->SetInteger("source_node_id", source_node_id);
   value->SetInteger("sorting_context_id", sorting_context_id);
+  value->SetInteger("flattens_inherited_transform",
+                    flattens_inherited_transform);
   MathUtil::AddToTracedValue("scroll_offset", scroll_offset, value);
   MathUtil::AddToTracedValue("snap_amount", snap_amount, value);
 }

third_party/blink/renderer/core/paint/compositing/graphics_layer_tree_as_text.cc

@@ -4,6 +4,7 @@
 
 #include "third_party/blink/renderer/core/paint/compositing/graphics_layer_tree_as_text.h"
 
+#include "cc/layers/picture_layer.h"
 #include "third_party/blink/renderer/core/scroll/scrollable_area.h"
 #include "third_party/blink/renderer/platform/geometry/geometry_as_json.h"
 #include "third_party/blink/renderer/platform/graphics/graphics_layer.h"
@@ -68,8 +69,12 @@ std::unique_ptr<JSONObject> GraphicsLayerAsJSON(
     const FloatPoint& position) {
   std::unique_ptr<JSONObject> json = JSONObject::Create();
 
-  if (flags & kLayerTreeIncludesDebugInfo)
+  if (flags & kLayerTreeIncludesDebugInfo) {
     json->SetString("this", PointerAsString(layer));
+    json->SetInteger("ccLayerId", layer->CcLayer()->id());
+    if (layer->HasContentsLayer())
+      json->SetInteger("ccContentsLayerId", layer->ContentsLayer()->id());
+  }
 
   json->SetString("name", layer->DebugName());