Track slow paths in DisplayItemList

cc/layers/picture_layer.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/layers/picture_layer.h"
 
 #include "base/auto_reset.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/layers/content_layer_client.h"
 #include "cc/layers/picture_layer_impl.h"
 #include "cc/layers/recording_source.h"
 #include "cc/paint/paint_record.h"
 #include "cc/trees/layer_tree_host.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "cc/trees/transform_node.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 
+static constexpr int kMaxNumberOfSlowPathsBeforeVeto = 5;
+
 namespace cc {
 
 PictureLayer::PictureLayerInputs::PictureLayerInputs() = default;
 
 PictureLayer::PictureLayerInputs::~PictureLayerInputs() = default;
 
 scoped_refptr<PictureLayer> PictureLayer::Create(ContentLayerClient* client) {
   return make_scoped_refptr(new PictureLayer(client));
 }
 
@@ skipping 153 matching lines @@
 
   return raster_source->GetFlattenedPicture();
 }
 
 bool PictureLayer::IsSuitableForGpuRasterization() const {
   // The display list needs to be created (see: UpdateAndExpandInvalidation)
   // before checking for suitability. There are cases where an update will not
   // create a display list (e.g., if the size is empty). We return true in these
   // cases because the gpu suitability bit sticks false.
   return !picture_layer_inputs_.display_list ||
-         picture_layer_inputs_.display_list->IsSuitableForGpuRasterization();
+         picture_layer_inputs_.display_list->NumSlowPaths() <=
+             kMaxNumberOfSlowPathsBeforeVeto;
 }
 
 void PictureLayer::ClearClient() {
   picture_layer_inputs_.client = nullptr;
   UpdateDrawsContent(HasDrawableContent());
 }
 
 void PictureLayer::SetNearestNeighbor(bool nearest_neighbor) {
   if (picture_layer_inputs_.nearest_neighbor == nearest_neighbor)
     return;
@@ skipping 81 matching lines @@
     return false;
 
   return true;
 }
 
 const DisplayItemList* PictureLayer::GetDisplayItemList() {
   return picture_layer_inputs_.display_list.get();
 }
 
 }  // namespace cc