cc : Stop pushing layers from hidden subtrees at commit

cc/layers/layer.cc

 // Copyright 2010 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/layer.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 70 matching lines @@
       // Layer IDs start from 1.
       inputs_(g_next_layer_id.GetNext() + 1),
       num_descendants_that_draw_content_(0),
       transform_tree_index_(TransformTree::kInvalidNodeId),
       effect_tree_index_(EffectTree::kInvalidNodeId),
       clip_tree_index_(ClipTree::kInvalidNodeId),
       scroll_tree_index_(ScrollTree::kInvalidNodeId),
       property_tree_sequence_number_(-1),
       should_flatten_transform_from_property_tree_(false),
       draws_content_(false),
+      is_hidden_(false),
       should_check_backface_visibility_(false),
       force_render_surface_for_testing_(false),
       subtree_property_changed_(false),
       may_contain_video_(false),
       is_scroll_clip_layer_(false),
       needs_show_scrollbars_(false),
       has_transform_node_(false),
       has_scroll_node_(false),
       subtree_has_copy_request_(false),
       safe_opaque_background_color_(0),
@@ skipping 1188 matching lines @@
     return inputs_.client->TakeDebugInfo(this);
   else
     return nullptr;
 }
 
 void Layer::didUpdateMainThreadScrollingReasons() {
   if (inputs_.client)
     inputs_.client->didUpdateMainThreadScrollingReasons();
 }
 
+void Layer::SetIsHidden(bool is_hidden) {
+  DCHECK(layer_tree_host_);
+  if (is_hidden == is_hidden_)
+    return;
+  is_hidden_ = is_hidden;
+  // We don't push layers that are hidden to compositor thread at commit. So,
+  // we need a full tree sync when is_hidden changes.
+  layer_tree_host_->SetNeedsFullTreeSync();
+}
+
 void Layer::SetSubtreePropertyChanged() {
   if (subtree_property_changed_)
     return;
   subtree_property_changed_ = true;
   SetNeedsPushProperties();
 }
 
 void Layer::SetMayContainVideo(bool yes) {
   if (may_contain_video_ == yes)
     return;
@@ skipping 138 matching lines @@
       ->subtree_has_copy_request;
 }
 
 gfx::Transform Layer::ScreenSpaceTransform() const {
   DCHECK_NE(transform_tree_index_, TransformTree::kInvalidNodeId);
   return draw_property_utils::ScreenSpaceTransform(
       this, layer_tree_host_->property_trees()->transform_tree);
 }
 
 }  // namespace cc