Harmonize LayerTreeHost/LayerTreeHostImpl synchronization steps

cc/trees/layer_tree_impl.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_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 33 matching lines @@
 #include "cc/trees/scroll_node.h"
 #include "cc/trees/transform_node.h"
 #include "ui/gfx/geometry/box_f.h"
 #include "ui/gfx/geometry/point_conversions.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 #include "ui/gfx/geometry/size_conversions.h"
 #include "ui/gfx/geometry/vector2d_conversions.h"
 
 namespace cc {
 
+void LayerTreeLifecycle::AdvanceTo(LifecycleState next_state) {
+  switch (next_state) {
+    case (kNotSyncing):
+      DCHECK_EQ(state_, kLastSyncState);
+      break;
+    case (kBeginningSync):
+    case (kSyncedPropertyTrees):
+    case (kSyncedLayerProperties):
+      // Only allow tree synchronization states to be transitioned in order.
+      DCHECK_EQ(state_ + 1, next_state);
+      break;
+  }
+  state_ = next_state;
+}
+
 LayerTreeImpl::LayerTreeImpl(
     LayerTreeHostImpl* layer_tree_host_impl,
     scoped_refptr<SyncedProperty<ScaleGroup>> page_scale_factor,
     scoped_refptr<SyncedBrowserControls> top_controls_shown_ratio,
     scoped_refptr<SyncedElasticOverscroll> elastic_overscroll)
     : layer_tree_host_impl_(layer_tree_host_impl),
       source_frame_number_(-1),
       is_first_frame_after_commit_tracker_(-1),
       root_layer_for_testing_(nullptr),
       hud_layer_(nullptr),
@@ skipping 91 matching lines @@
     DCHECK(OuterViewportContainerLayer()->viewport_layer_type() ==
            OUTER_VIEWPORT_CONTAINER);
 #endif
   if (auto* layer = LayerById(id))
     return layer->viewport_layer_type() != NOT_VIEWPORT_LAYER;
   return false;
 }
 
 void LayerTreeImpl::DidUpdateScrollOffset(int layer_id) {
   DidUpdateScrollState(layer_id);
+  DCHECK(lifecycle().AllowsPropertyTreeAccess());
   TransformTree& transform_tree = property_trees()->transform_tree;
   ScrollTree& scroll_tree = property_trees()->scroll_tree;
   int transform_id = TransformTree::kInvalidNodeId;
 
   // If pending tree topology changed and we still want to notify the pending
   // tree about scroll offset in the active tree, we may not find the
   // corresponding pending layer.
   if (LayerById(layer_id)) {
     // TODO(sunxd): when we have a layer_id to property_tree index map in
     // property trees, use the transform_id parameter instead of looking for
@@ skipping 17 matching lines @@
   }
 
   if (IsActiveTree() && layer_tree_host_impl_->pending_tree())
     layer_tree_host_impl_->pending_tree()->DidUpdateScrollOffset(layer_id);
 }
 
 void LayerTreeImpl::DidUpdateScrollState(int layer_id) {
   if (!IsActiveTree())
     return;
 
+  // The scroll_clip_layer Layer properties should be up-to-date.
+  // TODO(pdr): This DCHECK fails on existing tests but should be enabled.
+  // DCHECK(lifecycle().AllowsLayerPropertyAccess());
+
   if (layer_id == Layer::INVALID_ID)
     return;
 
   int scroll_layer_id, clip_layer_id;
   if (IsViewportLayerId(layer_id)) {
     if (!InnerViewportContainerLayer())
       return;
 
     // For scrollbar purposes, a change to any of the four viewport layers
     // should affect the scrollbars tied to the outermost layers, which express
@@ skipping 163 matching lines @@
       property_trees_.effect_tree.CreateOrReuseRenderSurfaces(
           &old_render_surfaces, this);
   if (render_surfaces_changed)
     set_needs_update_draw_properties();
   property_trees->effect_tree.PushCopyRequestsTo(&property_trees_.effect_tree);
   property_trees_.is_main_thread = false;
   property_trees_.is_active = IsActiveTree();
   property_trees_.transform_tree.set_source_to_parent_updates_allowed(false);
 }
 
-void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
-  // The request queue should have been processed and does not require a push.
-  DCHECK_EQ(ui_resource_request_queue_.size(), 0u);
+void LayerTreeImpl::PushPropertyTreesTo(LayerTreeImpl* target_tree) {
+  // Property trees may store damage status. We preserve the active tree
+  // damage status by pushing the damage status from active tree property
+  // trees to pending tree property trees or by moving it onto the layers.
+  if (target_tree->property_trees()->changed) {
+    if (property_trees()->sequence_number ==
+        target_tree->property_trees()->sequence_number)
+      target_tree->property_trees()->PushChangeTrackingTo(property_trees());
+    else
+      target_tree->MoveChangeTrackingToLayers();
+  }
 
   // To maintain the current scrolling node we need to use element ids which
   // are stable across the property tree update in SetPropertyTrees.
   ElementId scrolling_element_id;
   if (ScrollNode* scrolling_node = target_tree->CurrentlyScrollingNode())
     scrolling_element_id = scrolling_node->element_id;
 
   target_tree->SetPropertyTrees(&property_trees_);
 
   ScrollNode* scrolling_node = nullptr;
   if (scrolling_element_id) {
     auto& scroll_tree = target_tree->property_trees()->scroll_tree;
     scrolling_node = scroll_tree.FindNodeFromElementId(scrolling_element_id);
   }
   target_tree->SetCurrentlyScrollingNode(scrolling_node);
+}
+
+void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
+  // The request queue should have been processed and does not require a push.
+  DCHECK_EQ(ui_resource_request_queue_.size(), 0u);
 
   target_tree->property_trees()->scroll_tree.PushScrollUpdatesFromPendingTree(
       &property_trees_, target_tree);
 
   if (next_activation_forces_redraw_) {
     target_tree->ForceRedrawNextActivation();
     next_activation_forces_redraw_ = false;
   }
 
   target_tree->PassSwapPromises(std::move(swap_promise_list_));
@@ skipping 343 matching lines @@
     ++element_id_to_transform;
   }
 
   LayerTreeHostCommon::CallFunctionForEveryLayer(this, [](LayerImpl* layer) {
     layer->UpdatePropertyTreeForScrollingAndAnimationIfNeeded();
   });
 }
 
 void LayerTreeImpl::SetPageScaleOnActiveTree(float active_page_scale) {
   DCHECK(IsActiveTree());
+  DCHECK(lifecycle().AllowsPropertyTreeAccess());
   if (page_scale_factor()->SetCurrent(
           ClampPageScaleFactorToLimits(active_page_scale))) {
     DidUpdatePageScale();
     if (PageScaleLayer()) {
       draw_property_utils::UpdatePageScaleFactor(
           property_trees(), PageScaleLayer(), current_page_scale_factor(),
           device_scale_factor(), layer_tree_host_impl_->DrawTransform());
     } else {
       DCHECK(layer_list_.empty() || active_page_scale == 1);
     }
@@ skipping 30 matching lines @@
     // TODO(enne): Pushing from pending to active should never require
     // DidUpdatePageScale.  The values should already be set by the fully
     // computed property trees being synced from one tree to another.  Remove
     // this once CDP goes away.
     changed_page_scale |= page_scale_factor_->PushPendingToActive();
   }
 
   if (changed_page_scale)
     DidUpdatePageScale();
 
+  DCHECK(lifecycle().AllowsPropertyTreeAccess());
   if (page_scale_factor) {
     if (PageScaleLayer()) {
       draw_property_utils::UpdatePageScaleFactor(
           property_trees(), PageScaleLayer(), current_page_scale_factor(),
           device_scale_factor(), layer_tree_host_impl_->DrawTransform());
     } else {
       DCHECK(layer_list_.empty() || *page_scale_factor == 1);
     }
   }
 }
@@ skipping 156 matching lines @@
 
   UpdateViewportLayerTypes();
 }
 
 void LayerTreeImpl::ClearViewportLayers() {
   SetViewportLayersFromIds(Layer::INVALID_ID, Layer::INVALID_ID,
                            Layer::INVALID_ID, Layer::INVALID_ID);
 }
 
 void LayerTreeImpl::UpdateViewportLayerTypes() {
+  // The scroll_clip_layer Layer properties should be up-to-date.
+  // TODO(pdr): Enable this DCHECK by not calling this function unnecessarily
+  // from LayerImpl::SetScrollClipLayer.
+  // DCHECK(lifecycle().AllowsLayerPropertyAccess());
+
   if (auto* inner_scroll = LayerById(inner_viewport_scroll_layer_id_)) {
     inner_scroll->SetViewportLayerType(INNER_VIEWPORT_SCROLL);
     if (auto* inner_container = inner_scroll->scroll_clip_layer())
       inner_container->SetViewportLayerType(INNER_VIEWPORT_CONTAINER);
   }
   if (auto* outer_scroll = LayerById(outer_viewport_scroll_layer_id_)) {
     outer_scroll->SetViewportLayerType(OUTER_VIEWPORT_SCROLL);
     if (auto* outer_container = outer_scroll->scroll_clip_layer())
       outer_container->SetViewportLayerType(OUTER_VIEWPORT_CONTAINER);
   }
@@ skipping 1103 matching lines @@
 
 void LayerTreeImpl::ResetAllChangeTracking() {
   layers_that_should_push_properties_.clear();
   // Iterate over all layers, including masks.
   for (auto& layer : *layers_)
     layer->ResetChangeTracking();
   property_trees_.ResetAllChangeTracking();
 }
 
 }  // namespace cc