Add JSON generators for for debugging

Change-Id: I87fca2b760bb07100a12a02cb25556438cc57fd1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2072936Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: Stefan Zager <szager@chromium.org>
Cr-Commit-Position: refs/heads/master@{#744711}

third_party/blink/renderer/platform/graphics/compositing/paint_artifact_compositor.cc

@@ -13,6 +13,7 @@
 #include "cc/trees/layer_tree_host.h"
 #include "cc/trees/mutator_host.h"
 #include "third_party/blink/public/platform/platform.h"
+#include "third_party/blink/renderer/platform/geometry/geometry_as_json.h"
 #include "third_party/blink/renderer/platform/graphics/compositing/content_layer_client_impl.h"
 #include "third_party/blink/renderer/platform/graphics/graphics_context.h"
 #include "third_party/blink/renderer/platform/graphics/paint/clip_paint_property_node.h"
@@ -60,6 +61,14 @@ void PaintArtifactCompositor::WillBeRemovedFromFrame() {
   root_layer_->RemoveAllChildren();
 }
 
+std::unique_ptr<JSONArray> PaintArtifactCompositor::GetPendingLayersAsJSON(
+    const PaintArtifact* paint_artifact) const {
+  std::unique_ptr<JSONArray> result = std::make_unique<JSONArray>();
+  for (const PendingLayer& pending_layer : pending_layers_)
+    result->PushObject(pending_layer.ToJSON(paint_artifact));
+  return result;
+}
+
 // Get a JSON representation of what layers exist for this PAC.  Note that
 // |paint_artifact| is only needed for pre-CAP mode.
 std::unique_ptr<JSONObject> PaintArtifactCompositor::GetLayersAsJSON(
@@ -477,6 +486,30 @@ FloatRect PaintArtifactCompositor::PendingLayer::MapRectKnownToBeOpaque(
   return float_clip_rect.IsTight() ? float_clip_rect.Rect() : FloatRect();
 }
 
+std::unique_ptr<JSONObject> PaintArtifactCompositor::PendingLayer::ToJSON(
+    const PaintArtifact* paint_artifact) const {
+  std::unique_ptr<JSONObject> result = std::make_unique<JSONObject>();
+  result->SetArray("bounds", RectAsJSONArray(bounds));
+  result->SetArray("rect_known_to_be_opaque",
+                   RectAsJSONArray(rect_known_to_be_opaque));
+  result->SetObject("property_tree_state", property_tree_state.ToJSON());
+  result->SetArray("offset_of_decomposited_transforms",
+                   PointAsJSONArray(offset_of_decomposited_transforms));
+  std::unique_ptr<JSONArray> chunks = std::make_unique<JSONArray>();
+  for (wtf_size_t chunk_index : paint_chunk_indices) {
+    if (paint_artifact) {
+      StringBuilder sb;
+      sb.AppendFormat("index=%i ", chunk_index);
+      sb.Append(paint_artifact->PaintChunks()[chunk_index].ToString());
+      chunks->PushString(sb.ToString());
+    } else {
+      chunks->PushInteger(chunk_index);
+    }
+  }
+  result->SetArray("paint_chunks", std::move(chunks));
+  return result;
+}
+
 FloatRect PaintArtifactCompositor::PendingLayer::VisualRectForOverlapTesting()
     const {
   FloatClipRect visual_rect(bounds);

third_party/blink/renderer/platform/graphics/compositing/paint_artifact_compositor.h

@@ -167,6 +167,9 @@ class PLATFORM_EXPORT PaintArtifactCompositor final
   // going to be removed from its frame.
   void WillBeRemovedFromFrame();
 
+  std::unique_ptr<JSONArray> GetPendingLayersAsJSON(
+      const PaintArtifact* = nullptr) const;
+
   std::unique_ptr<JSONObject> GetLayersAsJSON(
       LayerTreeFlags,
       const PaintArtifact* = nullptr) const;
@@ -252,6 +255,8 @@ class PLATFORM_EXPORT PaintArtifactCompositor final
                                                const FloatRect&);
     FloatRect MapRectKnownToBeOpaque(const PropertyTreeState&) const;
 
+    std::unique_ptr<JSONObject> ToJSON(const PaintArtifact* = nullptr) const;
+
     FloatRect VisualRectForOverlapTesting() const;
 
     // The rects are in the space of property_tree_state.

third_party/blink/renderer/platform/graphics/paint/property_tree_state.cc

@@ -49,6 +49,14 @@ String PropertyTreeState::ToTreeString() const {
 
 #endif
 
+std::unique_ptr<JSONObject> PropertyTreeState::ToJSON() const {
+  std::unique_ptr<JSONObject> result = std::make_unique<JSONObject>();
+  result->SetObject("transform", transform_->ToJSON());
+  result->SetObject("clip", clip_->ToJSON());
+  result->SetObject("effect", effect_->ToJSON());
+  return result;
+}
+
 size_t PropertyTreeState::CacheMemoryUsageInBytes() const {
   return Clip().CacheMemoryUsageInBytes() +
          Transform().CacheMemoryUsageInBytes();

third_party/blink/renderer/platform/graphics/paint/property_tree_state.h

@@ -79,6 +79,7 @@ class PLATFORM_EXPORT PropertyTreeState {
   // Dumps the tree from this state up to the root as a string.
   String ToTreeString() const;
 #endif
+  std::unique_ptr<JSONObject> ToJSON() const;
 
   // Returns memory usage of the transform & clip caches of this state plus
   // ancestors.