cc : Remove subtree skipping in LayerTreeHostCommon

cc/trees/layer_tree_host_common.cc

 // Copyright 2011 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/trees/layer_tree_host_common.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 523 matching lines @@
   bool layer_is_drawn;
   DCHECK_GE(layer->effect_tree_index(), 0);
   layer_is_drawn = property_trees->effect_tree.Node(layer->effect_tree_index())
                        ->data.is_drawn;
 
   // The root layer cannot be skipped.
   if (!IsRootLayer(layer) &&
       draw_property_utils::LayerShouldBeSkipped(
           layer, layer_is_drawn, property_trees->transform_tree)) {
     layer->draw_properties().render_target = nullptr;
-    return;
-  }
+  } else {
+    bool render_to_separate_surface =
+        IsRootLayer(layer) ||
+        (can_render_to_separate_surface && layer->render_surface());
 
-  bool render_to_separate_surface =
-      IsRootLayer(layer) ||
-      (can_render_to_separate_surface && layer->render_surface());
+    if (render_to_separate_surface) {
+      DCHECK(layer->render_surface()) << IsRootLayer(layer)
+                                      << can_render_to_separate_surface
+                                      << layer->has_render_surface();
+      layer->draw_properties().render_target = layer;
 
-  if (render_to_separate_surface) {
-    DCHECK(layer->render_surface()) << IsRootLayer(layer)
-                                    << can_render_to_separate_surface
-                                    << layer->has_render_surface();
-    layer->draw_properties().render_target = layer;
+      if (layer->mask_layer())
+        layer->mask_layer()->draw_properties().render_target = layer;
 
-    if (layer->mask_layer())
-      layer->mask_layer()->draw_properties().render_target = layer;
+      if (layer->replica_layer() && layer->replica_layer()->mask_layer())
+        layer->replica_layer()->mask_layer()->draw_properties().render_target =
+            layer;
 
-    if (layer->replica_layer() && layer->replica_layer()->mask_layer())
-      layer->replica_layer()->mask_layer()->draw_properties().render_target =
-          layer;
-
-  } else {
-    DCHECK(!IsRootLayer(layer));
-    layer->draw_properties().render_target = layer->parent()->render_target();
+    } else {
+      DCHECK(!IsRootLayer(layer));
+      layer->draw_properties().render_target = layer->parent()->render_target();
+    }
   }
   for (size_t i = 0; i < layer->children().size(); ++i) {
     CalculateRenderTarget(
         LayerTreeHostCommon::get_layer_as_raw_ptr(layer->children(), i),
         property_trees, layer_is_drawn, can_render_to_separate_surface);
   }
 }
 
 void CalculateRenderSurfaceLayerList(
     LayerImpl* layer,
@@ skipping 25 matching lines @@
   layer_is_drawn = property_trees->effect_tree.Node(layer->effect_tree_index())
                        ->data.is_drawn;
 
   // The root layer cannot be skipped.
   if (!IsRootLayer(layer) &&
       draw_property_utils::LayerShouldBeSkipped(
           layer, layer_is_drawn, property_trees->transform_tree)) {
     if (layer->render_surface())
       layer->ClearRenderSurfaceLayerList();
     layer->draw_properties().render_target = nullptr;
+    for (auto* child_layer : layer->children()) {
+      CalculateRenderSurfaceLayerList(
+          child_layer, property_trees, render_surface_layer_list, descendants,
+          nearest_occlusion_immune_ancestor, layer_is_drawn,
+          can_render_to_separate_surface, current_render_surface_layer_list_id,
+          max_texture_size);
+    }
     return;
   }
 
   bool render_to_separate_surface =
       IsRootLayer(layer) ||
       (can_render_to_separate_surface && layer->render_surface());
 
   if (render_to_separate_surface) {
     DCHECK(layer->render_surface());
     draw_property_utils::ComputeSurfaceDrawProperties(property_trees,
@@ skipping 26 matching lines @@
     }
     layer->render_surface()->SetNearestOcclusionImmuneAncestor(
         nearest_occlusion_immune_ancestor);
     layer->ClearRenderSurfaceLayerList();
 
     render_surface_layer_list->push_back(layer);
 
     descendants = &(layer->render_surface()->layer_list());
   }
 
-  size_t descendants_size = descendants->size();
-
   bool layer_should_be_skipped = !draw_property_utils::LayerNeedsUpdate(
       layer, layer_is_drawn, property_trees->transform_tree);
   if (!layer_should_be_skipped) {

[ajuma, 2016/04/07 15:19:56]

Please add a DCHECK here that we're either rendering to a separate surface or
have a non-null render target.

[jaydasika, 2016/04/07 17:00:55]

Done.

     MarkLayerWithRenderSurfaceLayerListId(layer,
                                           current_render_surface_layer_list_id);
     descendants->push_back(layer);
   }
 
 
   // Clear the old accumulated content rect of surface.
   if (render_to_separate_surface)
     layer->render_surface()->SetAccumulatedContentRect(gfx::Rect());
 
@@ skipping 58 matching lines @@
       }
       // The RenderSurfaceImpl backing texture cannot exceed the maximum
       // supported texture size.
       surface_content_rect.set_width(
           std::min(surface_content_rect.width(), max_texture_size));
       surface_content_rect.set_height(
           std::min(surface_content_rect.height(), max_texture_size));
       layer->render_surface()->SetContentRect(surface_content_rect);
     }
     const LayerImpl* parent_target = layer->parent()->render_target();
-    if (!IsRootLayer(parent_target)) {
+    if (parent_target && !IsRootLayer(parent_target)) {

[jaydasika, 2016/04/07 00:32:21]

Adding this because layers with copy requests may not always have parent_target.

[ajuma, 2016/04/07 15:19:56]

Can this happen now, or only after the layer skipping logic gets changed? (If it
can happen now, please add a test for this.)

[jaydasika, 2016/04/07 17:00:55]

Cannot happen now.

       gfx::Rect surface_content_rect =
           parent_target->render_surface()->accumulated_content_rect();
       if (render_to_separate_surface) {
         // If the layer owns a surface, then the content rect is in the wrong
         // space. Instead, we will use the surface's DrawableContentRect which
         // is in target space as required. We also need to clip it with the
         // target's clip if the target is clipped.
         surface_content_rect.Union(gfx::ToEnclosedRect(
             layer->render_surface()->DrawableContentRect()));
         if (parent_target->is_clipped())
           surface_content_rect.Intersect(parent_target->clip_rect());
       } else if (layer->DrawsContent()) {
         surface_content_rect.Union(layer->drawable_content_rect());
       }
       parent_target->render_surface()->SetAccumulatedContentRect(
           surface_content_rect);
     }
   } else {
     // The root layer's surface content rect is always the entire viewport.
     gfx::Rect viewport =
         gfx::ToEnclosingRect(property_trees->clip_tree.ViewportClip());
     layer->render_surface()->SetContentRect(viewport);
   }
 
   if (render_to_separate_surface && !IsRootLayer(layer) &&
       layer->render_surface()->DrawableContentRect().IsEmpty()) {
     RemoveSurfaceForEarlyExit(layer, render_surface_layer_list);
-    return;
-  }
-
-  // If neither this layer nor any of its children were added, early out.
-  if (descendants_size == descendants->size()) {
-    DCHECK(!render_to_separate_surface || IsRootLayer(layer));
-    return;
   }
 }
 
 static void ComputeMaskLayerDrawProperties(const LayerImpl* layer,
                                            LayerImpl* mask_layer) {
   DrawProperties& mask_layer_draw_properties = mask_layer->draw_properties();
   mask_layer_draw_properties.visible_layer_rect = gfx::Rect(layer->bounds());
   mask_layer_draw_properties.target_space_transform =
       layer->draw_properties().target_space_transform;
   mask_layer_draw_properties.screen_space_transform =
@@ skipping 80 matching lines @@
   }
 
   if (should_measure_property_tree_performance) {
     TRACE_EVENT_BEGIN0(TRACE_DISABLED_BY_DEFAULT("cc.debug.cdp-perf"),
                        "LayerTreeHostCommon::CalculateDrawProperties");
   }
 
   DCHECK(inputs->can_render_to_separate_surface ==
          inputs->property_trees->non_root_surfaces_enabled);
   const bool subtree_visible_from_ancestor = true;
-  for (auto* layer : *inputs->root_layer->layer_tree_impl())
-    layer->draw_properties().render_target = nullptr;
   CalculateRenderTarget(inputs->root_layer, inputs->property_trees,
                         subtree_visible_from_ancestor,
                         inputs->can_render_to_separate_surface);
   for (LayerImpl* layer : visible_layer_list) {
     draw_property_utils::ComputeLayerDrawProperties(
         layer, inputs->property_trees, inputs->layers_always_allowed_lcd_text,
         inputs->can_use_lcd_text);
     if (layer->mask_layer())
       ComputeMaskLayerDrawProperties(layer, layer->mask_layer());
     LayerImpl* replica_mask_layer =
@@ skipping 105 matching lines @@
 
 PropertyTrees* GetPropertyTrees(Layer* layer) {
   return layer->layer_tree_host()->property_trees();
 }
 
 PropertyTrees* GetPropertyTrees(LayerImpl* layer) {
   return layer->layer_tree_impl()->property_trees();
 }
 
 }  // namespace cc