adjust comments as per review feedback

flow/layers/clip_path_layer_unittests.cc

@@ -56,7 +56,7 @@ TEST_F(ClipPathLayerTest, PaintingCulledLayerDies) {
   auto layer = std::make_shared<ClipPathLayer>(layer_path, Clip::hardEdge);
   layer->Add(mock_layer);
 
-  preroll_context()->cull_rect = distant_bounds;  // Cull everything
+  preroll_context()->cull_rect = distant_bounds;  // Cull these children
 
   layer->Preroll(preroll_context(), initial_matrix);
   EXPECT_EQ(preroll_context()->cull_rect, distant_bounds);    // Untouched

flow/layers/clip_rect_layer_unittests.cc

@@ -54,7 +54,7 @@ TEST_F(ClipRectLayerTest, PaintingCulledLayerDies) {
   auto layer = std::make_shared<ClipRectLayer>(layer_bounds, Clip::hardEdge);
   layer->Add(mock_layer);
 
-  preroll_context()->cull_rect = distant_bounds;  // Cull everything
+  preroll_context()->cull_rect = distant_bounds;  // Cull these children
 
   layer->Preroll(preroll_context(), initial_matrix);
   EXPECT_EQ(preroll_context()->cull_rect, distant_bounds);    // Untouched

flow/layers/clip_rrect_layer_unittests.cc

@@ -59,7 +59,7 @@ TEST_F(ClipRRectLayerTest, PaintingCulledLayerDies) {
   auto layer = std::make_shared<ClipRRectLayer>(layer_rrect, Clip::hardEdge);
   layer->Add(mock_layer);
 
-  preroll_context()->cull_rect = distant_bounds;  // Cull everything
+  preroll_context()->cull_rect = distant_bounds;  // Cull these children
 
   layer->Preroll(preroll_context(), initial_matrix);
   EXPECT_EQ(preroll_context()->cull_rect, distant_bounds);    // Untouched

flow/layers/container_layer.cc

@@ -72,11 +72,11 @@ void ContainerLayer::PrerollChildren(PrerollContext* context,
 }
 
 void ContainerLayer::PaintChildren(PaintContext& context) const {
-  // needs_painting(context) is only valid for the PaintContext that
+  // We can no longer call FML_DCHECK here on the needs_painting(context)
+  // condition as that test is only valid for the PaintContext that
   // is initially handed to a layer's Paint() method. By the time the
   // layer calls PaintChildren(), though, it may have modified the
-  // PaintContext so we can no longer double-check the culling.
-  // FML_DCHECK(needs_painting(context));
+  // PaintContext so the test doesn't work in this "context".
 
   // Intentionally not tracing here as there should be no self-time
   // and the trace event on this common function has a small overhead.

flow/layers/layer.h

@@ -163,10 +163,10 @@ class Layer {
     needs_system_composite_ = value;
   }
 
-  // Returns the unclipped paint bounds in the layer's local coordinate
-  // system as determined during Preroll().  The bounds should include
-  // any transform or distortions performed by the layer itself, but not
-  // any transforms performed by its ancestors.
+  // Returns the paint bounds in the layer's local coordinate system
+  // as determined during Preroll().  The bounds should include any
+  // transform, clip or distortions performed by the layer itself,
+  // but not any similar modifications inherited from its ancestors.
   const SkRect& paint_bounds() const { return paint_bounds_; }
 
   // This must be set by the time Preroll() returns otherwise the layer will