Revert of cc: Move data to LayerTree from LayerTreeHost.

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index a1376f81655e1c22d9a80535057f2f9bd9f0de28..8e0493a8c1af61f5f87ab840f4ae5be1a468df18 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -68,6 +68,23 @@
 namespace cc {
 namespace {
 
+Layer* UpdateAndGetLayer(Layer* current_layer,
+                         int layer_id,
+                         LayerTree* layer_tree) {
+  if (layer_id == Layer::INVALID_ID) {
+    if (current_layer)
+      current_layer->SetLayerTreeHost(nullptr);
+
+    return nullptr;
+  }
+  Layer* layer = layer_tree->LayerById(layer_id);
+  DCHECK(layer);
+  if (current_layer && current_layer != layer)
+    current_layer->SetLayerTreeHost(nullptr);
+
+  return layer;
+}
+
 std::unique_ptr<base::trace_event::TracedValue>
 ComputeLayerTreeHostProtoSizeSplitAsValue(proto::LayerTreeHost* proto) {
   std::unique_ptr<base::trace_event::TracedValue> value(
@@ -101,11 +118,9 @@
   }
 
   value->SetInteger("TotalLayerTreeHostProtoSize", proto->ByteSize());
-  value->SetInteger("LayerTreeHierarchySize",
-                    proto->layer_tree().root_layer().ByteSize());
+  value->SetInteger("LayerTreeHierarchySize", proto->root_layer().ByteSize());
   value->SetInteger("LayerUpdatesSize", proto->layer_updates().ByteSize());
-  value->SetInteger("PropertyTreesSize",
-                    proto->layer_tree().property_trees().ByteSize());
+  value->SetInteger("PropertyTreesSize", proto->property_trees().ByteSize());
 
   // LayerUpdate size breakdown.
   value->SetInteger("TotalBasePropertiesSize",
@@ -197,29 +212,33 @@
 }
 
 LayerTreeHost::LayerTreeHost(InitParams* params, CompositorMode mode)
-    : LayerTreeHost(
-          params,
-          mode,
-          base::MakeUnique<LayerTree>(std::move(params->animation_host),
-                                      this)) {}
-
-LayerTreeHost::LayerTreeHost(InitParams* params,
-                             CompositorMode mode,
-                             std::unique_ptr<LayerTree> layer_tree)
     : micro_benchmark_controller_(this),
-      layer_tree_(std::move(layer_tree)),
       next_ui_resource_id_(1),
       compositor_mode_(mode),
+      needs_full_tree_sync_(true),
+      needs_meta_info_recomputation_(true),
       client_(params->client),
       source_frame_number_(0),
       rendering_stats_instrumentation_(RenderingStatsInstrumentation::Create()),
       output_surface_lost_(true),
       settings_(*params->settings),
       debug_state_(settings_.initial_debug_state),
+      top_controls_shrink_blink_size_(false),
+      top_controls_height_(0.f),
+      top_controls_shown_ratio_(0.f),
+      device_scale_factor_(1.f),
+      painted_device_scale_factor_(1.f),
       visible_(false),
+      page_scale_factor_(1.f),
+      min_page_scale_factor_(1.f),
+      max_page_scale_factor_(1.f),
       has_gpu_rasterization_trigger_(false),
       content_is_suitable_for_gpu_rasterization_(true),
       gpu_rasterization_histogram_recorded_(false),
+      background_color_(SK_ColorWHITE),
+      has_transparent_background_(false),
+      have_scroll_event_handlers_(false),
+      event_listener_properties_(),
       did_complete_scale_animation_(false),
       id_(s_layer_tree_host_sequence_number.GetNext() + 1),
       next_commit_forces_redraw_(false),
@@ -228,11 +247,11 @@
       task_graph_runner_(params->task_graph_runner),
       image_serialization_processor_(params->image_serialization_processor),
       surface_client_id_(0u),
-      next_surface_sequence_(1u) {
+      next_surface_sequence_(1u),
+      layer_tree_(std::move(params->animation_host)) {
   DCHECK(task_graph_runner_);
-  DCHECK(layer_tree_);
-
-  layer_tree_->animation_host()->SetMutatorHostClient(this);
+
+  layer_tree_.animation_host()->SetMutatorHostClient(this);
 
   rendering_stats_instrumentation_->set_record_rendering_stats(
       debug_state_.RecordRenderingStats());
@@ -343,15 +362,17 @@
   proxy_ = std::move(proxy);
   proxy_->Start(std::move(external_begin_frame_source));
 
-  layer_tree_->animation_host()->SetSupportsScrollAnimations(
+  layer_tree_.animation_host()->SetSupportsScrollAnimations(
       proxy_->SupportsImplScrolling());
 }
 
 LayerTreeHost::~LayerTreeHost() {
   TRACE_EVENT0("cc", "LayerTreeHost::~LayerTreeHost");
 
-  // Clear any references into the LayerTreeHost.
-  layer_tree_.reset();
+  layer_tree_.animation_host()->SetMutatorHostClient(nullptr);
+
+  if (root_layer_.get())
+    root_layer_->SetLayerTreeHost(NULL);
 
   DCHECK(swap_promise_monitor_.empty());
 
@@ -363,6 +384,16 @@
 
     // Proxy must be destroyed before the Task Runner Provider.
     proxy_ = nullptr;
+  }
+
+  // We must clear any pointers into the layer tree prior to destroying it.
+  RegisterViewportLayers(NULL, NULL, NULL, NULL);
+
+  if (root_layer_.get()) {
+    // The layer tree must be destroyed before the layer tree host. We've
+    // made a contract with our animation controllers that the animation_host
+    // will outlive them, and we must make good.
+    root_layer_ = NULL;
   }
 }
 
@@ -405,7 +436,7 @@
   TRACE_EVENT_IS_NEW_TRACE(&is_new_trace);
   if (is_new_trace &&
       frame_viewer_instrumentation::IsTracingLayerTreeSnapshots() &&
-      layer_tree_->root_layer()) {
+      root_layer()) {
     LayerTreeHostCommon::CallFunctionForEveryLayer(
         this, [](Layer* layer) { layer->DidBeginTracing(); });
   }
@@ -419,35 +450,104 @@
 
   sync_tree->set_source_frame_number(source_frame_number());
 
-  if (layer_tree_->needs_full_tree_sync())
-    TreeSynchronizer::SynchronizeTrees(layer_tree_->root_layer(), sync_tree);
-
-  layer_tree_->PushPropertiesTo(sync_tree);
+  if (needs_full_tree_sync_)
+    TreeSynchronizer::SynchronizeTrees(root_layer(), sync_tree);
+
+  sync_tree->set_needs_full_tree_sync(needs_full_tree_sync_);
+  needs_full_tree_sync_ = false;
+
+  if (hud_layer_.get()) {
+    LayerImpl* hud_impl = sync_tree->LayerById(hud_layer_->id());
+    sync_tree->set_hud_layer(static_cast<HeadsUpDisplayLayerImpl*>(hud_impl));
+  } else {
+    sync_tree->set_hud_layer(NULL);
+  }
+
+  sync_tree->set_background_color(background_color_);
+  sync_tree->set_has_transparent_background(has_transparent_background_);
+  sync_tree->set_have_scroll_event_handlers(have_scroll_event_handlers_);
+  sync_tree->set_event_listener_properties(
+      EventListenerClass::kTouchStartOrMove,
+      event_listener_properties(EventListenerClass::kTouchStartOrMove));
+  sync_tree->set_event_listener_properties(
+      EventListenerClass::kMouseWheel,
+      event_listener_properties(EventListenerClass::kMouseWheel));
+  sync_tree->set_event_listener_properties(
+      EventListenerClass::kTouchEndOrCancel,
+      event_listener_properties(EventListenerClass::kTouchEndOrCancel));
+
+  if (page_scale_layer_.get() && inner_viewport_scroll_layer_.get()) {
+    sync_tree->SetViewportLayersFromIds(
+        overscroll_elasticity_layer_.get() ? overscroll_elasticity_layer_->id()
+                                           : Layer::INVALID_ID,
+        page_scale_layer_->id(), inner_viewport_scroll_layer_->id(),
+        outer_viewport_scroll_layer_.get() ? outer_viewport_scroll_layer_->id()
+                                           : Layer::INVALID_ID);
+    DCHECK(inner_viewport_scroll_layer_->IsContainerForFixedPositionLayers());
+  } else {
+    sync_tree->ClearViewportLayers();
+  }
+
+  sync_tree->RegisterSelection(selection_);
+
+  bool property_trees_changed_on_active_tree =
+      sync_tree->IsActiveTree() && sync_tree->property_trees()->changed;
+  // Property trees may store damage status. We preserve the sync tree damage
+  // status by pushing the damage status from sync tree property trees to main
+  // thread property trees or by moving it onto the layers.
+  if (root_layer_ && property_trees_changed_on_active_tree) {
+    if (property_trees_.sequence_number ==
+        sync_tree->property_trees()->sequence_number)
+      sync_tree->property_trees()->PushChangeTrackingTo(&property_trees_);
+    else
+      sync_tree->MoveChangeTrackingToLayers();
+  }
+  // Setting property trees must happen before pushing the page scale.
+  sync_tree->SetPropertyTrees(&property_trees_);
+
+  sync_tree->PushPageScaleFromMainThread(
+      page_scale_factor_, min_page_scale_factor_, max_page_scale_factor_);
+  sync_tree->elastic_overscroll()->PushFromMainThread(elastic_overscroll_);
+  if (sync_tree->IsActiveTree())
+    sync_tree->elastic_overscroll()->PushPendingToActive();
 
   sync_tree->PassSwapPromises(std::move(swap_promise_list_));
+
+  sync_tree->set_top_controls_shrink_blink_size(
+      top_controls_shrink_blink_size_);
+  sync_tree->set_top_controls_height(top_controls_height_);
+  sync_tree->PushTopControlsFromMainThread(top_controls_shown_ratio_);
 
   host_impl->SetHasGpuRasterizationTrigger(has_gpu_rasterization_trigger_);
   host_impl->SetContentIsSuitableForGpuRasterization(
       content_is_suitable_for_gpu_rasterization_);
   RecordGpuRasterizationHistogram();
 
-  host_impl->SetViewportSize(layer_tree_->device_viewport_size());
-  // TODO(senorblanco): Move this to LayerTree::PushPropertiesTo so that it
-  // happens before GPU rasterization properties are set, since those trigger an
-  // update of GPU rasterization status, which depends on the device scale
-  // factor. (crbug.com/535700)
-  sync_tree->SetDeviceScaleFactor(layer_tree_->device_scale_factor());
+  host_impl->SetViewportSize(device_viewport_size_);
+  // TODO(senorblanco): Move this up so that it happens before GPU rasterization
+  // properties are set, since those trigger an update of GPU rasterization
+  // status, which depends on the device scale factor. (crbug.com/535700)
+  sync_tree->SetDeviceScaleFactor(device_scale_factor_);
+  sync_tree->set_painted_device_scale_factor(painted_device_scale_factor_);
   host_impl->SetDebugState(debug_state_);
+  if (pending_page_scale_animation_) {
+    sync_tree->SetPendingPageScaleAnimation(
+        std::move(pending_page_scale_animation_));
+  }
 
   if (!ui_resource_request_queue_.empty()) {
     sync_tree->set_ui_resource_request_queue(ui_resource_request_queue_);
     ui_resource_request_queue_.clear();
   }
 
+  DCHECK(!sync_tree->ViewportSizeInvalid());
+
+  sync_tree->set_has_ever_been_drawn(false);
+
   {
     TRACE_EVENT0("cc", "LayerTreeHost::PushProperties");
 
-    TreeSynchronizer::PushLayerProperties(layer_tree_.get(), sync_tree);
+    TreeSynchronizer::PushLayerProperties(&layer_tree_, sync_tree);
 
     // This must happen after synchronizing property trees and after push
     // properties, which updates property tree indices, but before animation
@@ -458,16 +558,15 @@
 
     TRACE_EVENT0("cc", "LayerTreeHost::AnimationHost::PushProperties");
     DCHECK(host_impl->animation_host());
-    layer_tree_->animation_host()->PushPropertiesTo(
-        host_impl->animation_host());
+    layer_tree_.animation_host()->PushPropertiesTo(host_impl->animation_host());
   }
 
   // This must happen after synchronizing property trees and after pushing
   // properties, which updates the clobber_active_value flag.
-  sync_tree->UpdatePropertyTreeScrollOffset(layer_tree_->property_trees());
+  sync_tree->UpdatePropertyTreeScrollOffset(&property_trees_);
 
   micro_benchmark_controller_.ScheduleImplBenchmarks(host_impl);
-  layer_tree_->property_trees()->ResetAllChangeTracking();
+  property_trees_.ResetAllChangeTracking();
 }
 
 void LayerTreeHost::WillCommit() {
@@ -476,6 +575,17 @@
 }
 
 void LayerTreeHost::UpdateHudLayer() {
+  if (debug_state_.ShowHudInfo()) {
+    if (!hud_layer_.get()) {
+      hud_layer_ = HeadsUpDisplayLayer::Create();
+    }
+
+    if (root_layer_.get() && !hud_layer_->parent())
+      root_layer_->AddChild(hud_layer_);
+  } else if (hud_layer_.get()) {
+    hud_layer_->RemoveFromParent();
+    hud_layer_ = NULL;
+  }
 }
 
 void LayerTreeHost::CommitComplete() {
@@ -535,8 +645,7 @@
 
   const bool supports_impl_scrolling = task_runner_provider_->HasImplThread();
   std::unique_ptr<AnimationHost> animation_host_impl =
-      layer_tree_->animation_host()->CreateImplInstance(
-          supports_impl_scrolling);
+      layer_tree_.animation_host()->CreateImplInstance(supports_impl_scrolling);
 
   std::unique_ptr<LayerTreeHostImpl> host_impl = LayerTreeHostImpl::Create(
       settings_, client, task_runner_provider_.get(),
@@ -587,13 +696,30 @@
   NotifySwapPromiseMonitorsOfSetNeedsCommit();
 }
 
+void LayerTreeHost::SetPropertyTreesNeedRebuild() {
+  property_trees_.needs_rebuild = true;
+  SetNeedsUpdateLayers();
+}
+
 void LayerTreeHost::SetNeedsCommit() {
   proxy_->SetNeedsCommit();
   NotifySwapPromiseMonitorsOfSetNeedsCommit();
 }
 
+void LayerTreeHost::SetNeedsFullTreeSync() {
+  needs_full_tree_sync_ = true;
+  needs_meta_info_recomputation_ = true;
+
+  property_trees_.needs_rebuild = true;
+  SetNeedsCommit();
+}
+
+void LayerTreeHost::SetNeedsMetaInfoRecomputation(bool needs_recomputation) {
+  needs_meta_info_recomputation_ = needs_recomputation;
+}
+
 void LayerTreeHost::SetNeedsRedraw() {
-  SetNeedsRedrawRect(gfx::Rect(layer_tree_->device_viewport_size()));
+  SetNeedsRedrawRect(gfx::Rect(device_viewport_size_));
 }
 
 void LayerTreeHost::SetNeedsRedrawRect(const gfx::Rect& damage_rect) {
@@ -620,7 +746,30 @@
 void LayerTreeHost::SetAnimationEvents(
     std::unique_ptr<AnimationEvents> events) {
   DCHECK(task_runner_provider_->IsMainThread());
-  layer_tree_->animation_host()->SetAnimationEvents(std::move(events));
+  layer_tree_.animation_host()->SetAnimationEvents(std::move(events));
+}
+
+void LayerTreeHost::SetRootLayer(scoped_refptr<Layer> root_layer) {
+  if (root_layer_.get() == root_layer.get())
+    return;
+
+  if (root_layer_.get())
+    root_layer_->SetLayerTreeHost(NULL);
+  root_layer_ = root_layer;
+  if (root_layer_.get()) {
+    DCHECK(!root_layer_->parent());
+    root_layer_->SetLayerTreeHost(this);
+  }
+
+  if (hud_layer_.get())
+    hud_layer_->RemoveFromParent();
+
+  // Reset gpu rasterization flag.
+  // This flag is sticky until a new tree comes along.
+  content_is_suitable_for_gpu_rasterization_ = true;
+  gpu_rasterization_histogram_recorded_ = false;
+
+  SetNeedsFullTreeSync();
 }
 
 void LayerTreeHost::SetDebugState(const LayerTreeDebugState& debug_state) {
@@ -636,11 +785,6 @@
       debug_state_.RecordRenderingStats());
 
   SetNeedsCommit();
-}
-
-void LayerTreeHost::ResetGpuRasterizationTracking() {
-  content_is_suitable_for_gpu_rasterization_ = true;
-  gpu_rasterization_histogram_recorded_ = false;
 }
 
 void LayerTreeHost::SetHasGpuRasterizationTrigger(bool has_trigger) {
@@ -655,12 +799,55 @@
                        has_gpu_rasterization_trigger_);
 }
 
+void LayerTreeHost::SetViewportSize(const gfx::Size& device_viewport_size) {
+  if (device_viewport_size == device_viewport_size_)
+    return;
+
+  device_viewport_size_ = device_viewport_size;
+
+  SetPropertyTreesNeedRebuild();
+  SetNeedsCommit();
+}
+
+void LayerTreeHost::SetTopControlsHeight(float height, bool shrink) {
+  if (top_controls_height_ == height &&
+      top_controls_shrink_blink_size_ == shrink)
+    return;
+
+  top_controls_height_ = height;
+  top_controls_shrink_blink_size_ = shrink;
+  SetNeedsCommit();
+}
+
+void LayerTreeHost::SetTopControlsShownRatio(float ratio) {
+  if (top_controls_shown_ratio_ == ratio)
+    return;
+
+  top_controls_shown_ratio_ = ratio;
+  SetNeedsCommit();
+}
+
 void LayerTreeHost::ApplyPageScaleDeltaFromImplSide(float page_scale_delta) {
   DCHECK(CommitRequested());
   if (page_scale_delta == 1.f)
     return;
-  float page_scale = layer_tree_->page_scale_factor() * page_scale_delta;
-  layer_tree_->SetPageScaleFromImplSide(page_scale);
+  page_scale_factor_ *= page_scale_delta;
+  SetPropertyTreesNeedRebuild();
+}
+
+void LayerTreeHost::SetPageScaleFactorAndLimits(float page_scale_factor,
+                                                float min_page_scale_factor,
+                                                float max_page_scale_factor) {
+  if (page_scale_factor == page_scale_factor_ &&
+      min_page_scale_factor == min_page_scale_factor_ &&
+      max_page_scale_factor == max_page_scale_factor_)
+    return;
+
+  page_scale_factor_ = page_scale_factor;
+  min_page_scale_factor_ = min_page_scale_factor;
+  max_page_scale_factor_ = max_page_scale_factor;
+  SetPropertyTreesNeedRebuild();
+  SetNeedsCommit();
 }
 
 void LayerTreeHost::SetVisible(bool visible) {
@@ -668,6 +855,24 @@
     return;
   visible_ = visible;
   proxy_->SetVisible(visible);
+}
+
+void LayerTreeHost::StartPageScaleAnimation(const gfx::Vector2d& target_offset,
+                                            bool use_anchor,
+                                            float scale,
+                                            base::TimeDelta duration) {
+  pending_page_scale_animation_.reset(
+      new PendingPageScaleAnimation(
+          target_offset,
+          use_anchor,
+          scale,
+          duration));
+
+  SetNeedsCommit();
+}
+
+bool LayerTreeHost::HasPendingPageScaleAnimation() const {
+  return !!pending_page_scale_animation_.get();
 }
 
 void LayerTreeHost::NotifyInputThrottledUntilCommit() {
@@ -703,16 +908,16 @@
 
 bool LayerTreeHost::UpdateLayers() {
   DCHECK(!output_surface_lost_);
-  if (!layer_tree_->root_layer())
+  if (!root_layer())
     return false;
-  DCHECK(!layer_tree_->root_layer()->parent());
-  bool result = DoUpdateLayers(layer_tree_->root_layer());
+  DCHECK(!root_layer()->parent());
+  bool result = DoUpdateLayers(root_layer());
   micro_benchmark_controller_.DidUpdateLayers();
   return result || next_commit_forces_redraw_;
 }
 
 LayerListIterator<Layer> LayerTreeHost::begin() const {
-  return LayerListIterator<Layer>(layer_tree_->root_layer());
+  return LayerListIterator<Layer>(root_layer_.get());
 }
 
 LayerListIterator<Layer> LayerTreeHost::end() const {
@@ -720,7 +925,7 @@
 }
 
 LayerListReverseIterator<Layer> LayerTreeHost::rbegin() {
-  return LayerListReverseIterator<Layer>(layer_tree_->root_layer());
+  return LayerListReverseIterator<Layer>(root_layer_.get());
 }
 
 LayerListReverseIterator<Layer> LayerTreeHost::rend() {
@@ -758,16 +963,14 @@
 }
 
 void LayerTreeHost::BuildPropertyTreesForTesting() {
-  PropertyTreeBuilder::PreCalculateMetaInformation(layer_tree_->root_layer());
+  PropertyTreeBuilder::PreCalculateMetaInformation(root_layer_.get());
   gfx::Transform identity_transform;
   PropertyTreeBuilder::BuildPropertyTrees(
-      layer_tree_->root_layer(), layer_tree_->page_scale_layer(),
-      layer_tree_->inner_viewport_scroll_layer(),
-      layer_tree_->outer_viewport_scroll_layer(),
-      layer_tree_->overscroll_elasticity_layer(), elastic_overscroll_,
-      layer_tree_->page_scale_factor(), layer_tree_->device_scale_factor(),
-      gfx::Rect(layer_tree_->device_viewport_size()), identity_transform,
-      layer_tree_->property_trees());
+      root_layer_.get(), page_scale_layer_.get(),
+      inner_viewport_scroll_layer_.get(), outer_viewport_scroll_layer_.get(),
+      overscroll_elasticity_layer_.get(), elastic_overscroll_,
+      page_scale_factor_, device_scale_factor_,
+      gfx::Rect(device_viewport_size_), identity_transform, &property_trees_);
 }
 
 static void SetElementIdForTesting(Layer* layer) {
@@ -786,19 +989,17 @@
   TRACE_EVENT1("cc", "LayerTreeHost::DoUpdateLayers", "source_frame_number",
                source_frame_number());
 
-  layer_tree_->UpdateHudLayer(debug_state_.ShowHudInfo());
   UpdateHudLayer();
 
   Layer* root_scroll =
       PropertyTreeBuilder::FindFirstScrollableLayer(root_layer);
-  Layer* page_scale_layer = layer_tree_->page_scale_layer();
+  Layer* page_scale_layer = page_scale_layer_.get();
   if (!page_scale_layer && root_scroll)
     page_scale_layer = root_scroll->parent();
 
-  if (layer_tree_->hud_layer()) {
-    layer_tree_->hud_layer()->PrepareForCalculateDrawProperties(
-        layer_tree_->device_viewport_size(),
-        layer_tree_->device_scale_factor());
+  if (hud_layer_.get()) {
+    hud_layer_->PrepareForCalculateDrawProperties(device_viewport_size(),
+                                                  device_scale_factor_);
   }
 
   gfx::Transform identity_transform;
@@ -810,32 +1011,30 @@
                  "LayerTreeHostCommon::ComputeVisibleRectsWithPropertyTrees");
     PropertyTreeBuilder::PreCalculateMetaInformation(root_layer);
     bool can_render_to_separate_surface = true;
-    PropertyTrees* property_trees = layer_tree_->property_trees();
     if (!settings_.use_layer_lists) {
       // If use_layer_lists is set, then the property trees should have been
       // built by the client already.
       PropertyTreeBuilder::BuildPropertyTrees(
-          root_layer, page_scale_layer,
-          layer_tree_->inner_viewport_scroll_layer(),
-          layer_tree_->outer_viewport_scroll_layer(),
-          layer_tree_->overscroll_elasticity_layer(), elastic_overscroll_,
-          layer_tree_->page_scale_factor(), layer_tree_->device_scale_factor(),
-          gfx::Rect(layer_tree_->device_viewport_size()), identity_transform,
-          property_trees);
+          root_layer, page_scale_layer, inner_viewport_scroll_layer_.get(),
+          outer_viewport_scroll_layer_.get(),
+          overscroll_elasticity_layer_.get(), elastic_overscroll_,
+          page_scale_factor_, device_scale_factor_,
+          gfx::Rect(device_viewport_size_), identity_transform,
+          &property_trees_);
       TRACE_EVENT_INSTANT1("cc",
                            "LayerTreeHost::UpdateLayers_BuiltPropertyTrees",
                            TRACE_EVENT_SCOPE_THREAD, "property_trees",
-                           property_trees->AsTracedValue());
+                           property_trees_.AsTracedValue());
     } else {
       TRACE_EVENT_INSTANT1("cc",
                            "LayerTreeHost::UpdateLayers_ReceivedPropertyTrees",
                            TRACE_EVENT_SCOPE_THREAD, "property_trees",
-                           property_trees->AsTracedValue());
+                           property_trees_.AsTracedValue());
     }
-    draw_property_utils::UpdatePropertyTrees(property_trees,
+    draw_property_utils::UpdatePropertyTrees(&property_trees_,
                                              can_render_to_separate_surface);
     draw_property_utils::FindLayersThatNeedUpdates(
-        this, property_trees->transform_tree, property_trees->effect_tree,
+        this, property_trees_.transform_tree, property_trees_.effect_tree,
         &update_layer_list);
   }
 
@@ -843,8 +1042,8 @@
     layer->SavePaintProperties();
 
   bool content_is_suitable_for_gpu = true;
-  bool did_paint_content = layer_tree_->UpdateLayers(
-      update_layer_list, &content_is_suitable_for_gpu);
+  bool did_paint_content =
+      layer_tree_.UpdateLayers(update_layer_list, &content_is_suitable_for_gpu);
 
   if (content_is_suitable_for_gpu) {
     ++num_consecutive_frames_suitable_for_gpu_;
@@ -871,10 +1070,10 @@
   // Preemptively apply the scroll offset and scale delta here before sending
   // it to the client.  If the client comes back and sets it to the same
   // value, then the layer can early out without needing a full commit.
-  if (layer_tree_->inner_viewport_scroll_layer()) {
-    layer_tree_->inner_viewport_scroll_layer()->SetScrollOffsetFromImplSide(
+  if (inner_viewport_scroll_layer_.get()) {
+    inner_viewport_scroll_layer_->SetScrollOffsetFromImplSide(
         gfx::ScrollOffsetWithDelta(
-            layer_tree_->inner_viewport_scroll_layer()->scroll_offset(),
+            inner_viewport_scroll_layer_->scroll_offset(),
             inner_viewport_scroll_delta));
   }
 
@@ -899,7 +1098,7 @@
     QueueSwapPromise(std::move(swap_promise));
   }
 
-  if (layer_tree_->root_layer()) {
+  if (root_layer_.get()) {
     for (size_t i = 0; i < info->scrolls.size(); ++i) {
       Layer* layer = LayerById(info->scrolls[i].layer_id);
       if (!layer)
@@ -916,6 +1115,24 @@
   ApplyViewportDeltas(info);
 }
 
+void LayerTreeHost::SetDeviceScaleFactor(float device_scale_factor) {
+  if (device_scale_factor == device_scale_factor_)
+    return;
+  device_scale_factor_ = device_scale_factor;
+
+  property_trees_.needs_rebuild = true;
+  SetNeedsCommit();
+}
+
+void LayerTreeHost::SetPaintedDeviceScaleFactor(
+    float painted_device_scale_factor) {
+  if (painted_device_scale_factor == painted_device_scale_factor_)
+    return;
+  painted_device_scale_factor_ = painted_device_scale_factor;
+
+  SetNeedsCommit();
+}
+
 void LayerTreeHost::UpdateTopControlsState(TopControlsState constraints,
                                            TopControlsState current,
                                            bool animate) {
@@ -925,14 +1142,14 @@
 }
 
 void LayerTreeHost::AnimateLayers(base::TimeTicks monotonic_time) {
-  AnimationHost* animation_host = layer_tree_->animation_host();
+  AnimationHost* animation_host = layer_tree_.animation_host();
   std::unique_ptr<AnimationEvents> events = animation_host->CreateEvents();
 
   if (animation_host->AnimateLayers(monotonic_time))
     animation_host->UpdateAnimationState(true, events.get());
 
   if (!events->events_.empty())
-    layer_tree_->property_trees()->needs_rebuild = true;
+    property_trees_.needs_rebuild = true;
 }
 
 UIResourceId LayerTreeHost::CreateUIResource(UIResourceClient* client) {
@@ -989,6 +1206,46 @@
   return data.size;
 }
 
+void LayerTreeHost::RegisterViewportLayers(
+    scoped_refptr<Layer> overscroll_elasticity_layer,
+    scoped_refptr<Layer> page_scale_layer,
+    scoped_refptr<Layer> inner_viewport_scroll_layer,
+    scoped_refptr<Layer> outer_viewport_scroll_layer) {
+  DCHECK(!inner_viewport_scroll_layer ||
+         inner_viewport_scroll_layer != outer_viewport_scroll_layer);
+  overscroll_elasticity_layer_ = overscroll_elasticity_layer;
+  page_scale_layer_ = page_scale_layer;
+  inner_viewport_scroll_layer_ = inner_viewport_scroll_layer;
+  outer_viewport_scroll_layer_ = outer_viewport_scroll_layer;
+}
+
+void LayerTreeHost::RegisterSelection(const LayerSelection& selection) {
+  if (selection_ == selection)
+    return;
+
+  selection_ = selection;
+  SetNeedsCommit();
+}
+
+void LayerTreeHost::SetHaveScrollEventHandlers(bool have_event_handlers) {
+  if (have_scroll_event_handlers_ == have_event_handlers)
+    return;
+
+  have_scroll_event_handlers_ = have_event_handlers;
+  SetNeedsCommit();
+}
+
+void LayerTreeHost::SetEventListenerProperties(
+    EventListenerClass event_class,
+    EventListenerProperties properties) {
+  const size_t index = static_cast<size_t>(event_class);
+  if (event_listener_properties_[index] == properties)
+    return;
+
+  event_listener_properties_[index] = properties;
+  SetNeedsCommit();
+}
+
 int LayerTreeHost::ScheduleMicroBenchmark(
     const std::string& benchmark_name,
     std::unique_ptr<base::Value> value,
@@ -1054,7 +1311,7 @@
 }
 
 Layer* LayerTreeHost::LayerById(int id) const {
-  return layer_tree_->LayerById(id);
+  return layer_tree_.LayerById(id);
 }
 
 Layer* LayerTreeHost::LayerByElementId(ElementId element_id) const {
@@ -1086,7 +1343,7 @@
 }
 
 void LayerTreeHost::SetMutatorsNeedRebuildPropertyTrees() {
-  layer_tree_->property_trees()->needs_rebuild = true;
+  property_trees_.needs_rebuild = true;
 }
 
 void LayerTreeHost::SetElementFilterMutated(ElementId element_id,
@@ -1247,12 +1504,17 @@
   swap_promises->swap(swap_promise_list_);
   DCHECK(swap_promise_list_.empty());
 
+  proto->set_needs_full_tree_sync(needs_full_tree_sync_);
+  proto->set_needs_meta_info_recomputation(needs_meta_info_recomputation_);
   proto->set_source_frame_number(source_frame_number_);
+
+  LayerProtoConverter::SerializeLayerHierarchy(root_layer_,
+                                               proto->mutable_root_layer());
 
   // Serialize the LayerTree before serializing the properties. During layer
   // property serialization, we clear the list |layer_that_should_properties_|
   // from the LayerTree.
-  layer_tree_->ToProtobuf(proto->mutable_layer_tree());
+  layer_tree_.ToProtobuf(proto->mutable_layer_tree());
 
   LayerProtoConverter::SerializeLayerProperties(this,
                                                 proto->mutable_layer_updates());
@@ -1262,13 +1524,51 @@
   proto::PictureDataVectorToSkPicturesProto(pictures,
                                             proto->mutable_pictures());
 
+  proto->set_hud_layer_id(hud_layer_ ? hud_layer_->id() : Layer::INVALID_ID);
   debug_state_.ToProtobuf(proto->mutable_debug_state());
+  SizeToProto(device_viewport_size_, proto->mutable_device_viewport_size());
+  proto->set_top_controls_shrink_blink_size(top_controls_shrink_blink_size_);
+  proto->set_top_controls_height(top_controls_height_);
+  proto->set_top_controls_shown_ratio(top_controls_shown_ratio_);
+  proto->set_device_scale_factor(device_scale_factor_);
+  proto->set_painted_device_scale_factor(painted_device_scale_factor_);
+  proto->set_page_scale_factor(page_scale_factor_);
+  proto->set_min_page_scale_factor(min_page_scale_factor_);
+  proto->set_max_page_scale_factor(max_page_scale_factor_);
   Vector2dFToProto(elastic_overscroll_, proto->mutable_elastic_overscroll());
   proto->set_has_gpu_rasterization_trigger(has_gpu_rasterization_trigger_);
   proto->set_content_is_suitable_for_gpu_rasterization(
       content_is_suitable_for_gpu_rasterization_);
+  proto->set_background_color(background_color_);
+  proto->set_has_transparent_background(has_transparent_background_);
+  proto->set_have_scroll_event_handlers(have_scroll_event_handlers_);
+  proto->set_wheel_event_listener_properties(static_cast<uint32_t>(
+      event_listener_properties(EventListenerClass::kMouseWheel)));
+  proto->set_touch_start_or_move_event_listener_properties(
+      static_cast<uint32_t>(
+          event_listener_properties(EventListenerClass::kTouchStartOrMove)));
+  proto->set_touch_end_or_cancel_event_listener_properties(
+      static_cast<uint32_t>(
+          event_listener_properties(EventListenerClass::kTouchEndOrCancel)));
   proto->set_id(id_);
   proto->set_next_commit_forces_redraw(next_commit_forces_redraw_);
+
+  // Viewport layers.
+  proto->set_overscroll_elasticity_layer_id(
+      overscroll_elasticity_layer_ ? overscroll_elasticity_layer_->id()
+                                   : Layer::INVALID_ID);
+  proto->set_page_scale_layer_id(page_scale_layer_ ? page_scale_layer_->id()
+                                                   : Layer::INVALID_ID);
+  proto->set_inner_viewport_scroll_layer_id(
+      inner_viewport_scroll_layer_ ? inner_viewport_scroll_layer_->id()
+                                   : Layer::INVALID_ID);
+  proto->set_outer_viewport_scroll_layer_id(
+      outer_viewport_scroll_layer_ ? outer_viewport_scroll_layer_->id()
+                                   : Layer::INVALID_ID);
+
+  LayerSelectionToProtobuf(selection_, proto->mutable_selection());
+
+  property_trees_.ToProtobuf(proto->mutable_property_trees());
 
   proto->set_surface_client_id(surface_client_id_);
   proto->set_next_surface_sequence(next_surface_sequence_);
@@ -1280,9 +1580,19 @@
 
 void LayerTreeHost::FromProtobufForCommit(const proto::LayerTreeHost& proto) {
   DCHECK(client_picture_cache_);
+  needs_full_tree_sync_ = proto.needs_full_tree_sync();
+  needs_meta_info_recomputation_ = proto.needs_meta_info_recomputation();
   source_frame_number_ = proto.source_frame_number();
 
-  layer_tree_->FromProtobuf(proto.layer_tree());
+  // Layer hierarchy.
+  scoped_refptr<Layer> new_root_layer =
+      LayerProtoConverter::DeserializeLayerHierarchy(root_layer_,
+                                                     proto.root_layer(), this);
+  if (root_layer_ != new_root_layer) {
+    root_layer_ = new_root_layer;
+  }
+
+  layer_tree_.FromProtobuf(proto.layer_tree());
 
   // Ensure ClientPictureCache contains all the necessary SkPictures before
   // deserializing the properties.
@@ -1291,26 +1601,80 @@
       SkPicturesProtoToPictureDataVector(proto_pictures);
   client_picture_cache_->ApplyCacheUpdate(pictures);
 
-  LayerProtoConverter::DeserializeLayerProperties(layer_tree_->root_layer(),
+  LayerProtoConverter::DeserializeLayerProperties(root_layer_.get(),
                                                   proto.layer_updates());
 
   // The deserialization is finished, so now clear the cache.
   client_picture_cache_->Flush();
 
   debug_state_.FromProtobuf(proto.debug_state());
+  device_viewport_size_ = ProtoToSize(proto.device_viewport_size());
+  top_controls_shrink_blink_size_ = proto.top_controls_shrink_blink_size();
+  top_controls_height_ = proto.top_controls_height();
+  top_controls_shown_ratio_ = proto.top_controls_shown_ratio();
+  device_scale_factor_ = proto.device_scale_factor();
+  painted_device_scale_factor_ = proto.painted_device_scale_factor();
+  page_scale_factor_ = proto.page_scale_factor();
+  min_page_scale_factor_ = proto.min_page_scale_factor();
+  max_page_scale_factor_ = proto.max_page_scale_factor();
   elastic_overscroll_ = ProtoToVector2dF(proto.elastic_overscroll());
   has_gpu_rasterization_trigger_ = proto.has_gpu_rasterization_trigger();
   content_is_suitable_for_gpu_rasterization_ =
       proto.content_is_suitable_for_gpu_rasterization();
+  background_color_ = proto.background_color();
+  has_transparent_background_ = proto.has_transparent_background();
+  have_scroll_event_handlers_ = proto.have_scroll_event_handlers();
+  event_listener_properties_[static_cast<size_t>(
+      EventListenerClass::kMouseWheel)] =
+      static_cast<EventListenerProperties>(
+          proto.wheel_event_listener_properties());
+  event_listener_properties_[static_cast<size_t>(
+      EventListenerClass::kTouchStartOrMove)] =
+      static_cast<EventListenerProperties>(
+          proto.touch_start_or_move_event_listener_properties());
+  event_listener_properties_[static_cast<size_t>(
+      EventListenerClass::kTouchEndOrCancel)] =
+      static_cast<EventListenerProperties>(
+          proto.touch_end_or_cancel_event_listener_properties());
   id_ = proto.id();
   next_commit_forces_redraw_ = proto.next_commit_forces_redraw();
 
+  hud_layer_ = static_cast<HeadsUpDisplayLayer*>(
+      UpdateAndGetLayer(hud_layer_.get(), proto.hud_layer_id(), &layer_tree_));
+  overscroll_elasticity_layer_ =
+      UpdateAndGetLayer(overscroll_elasticity_layer_.get(),
+                        proto.overscroll_elasticity_layer_id(), &layer_tree_);
+  page_scale_layer_ = UpdateAndGetLayer(
+      page_scale_layer_.get(), proto.page_scale_layer_id(), &layer_tree_);
+  inner_viewport_scroll_layer_ =
+      UpdateAndGetLayer(inner_viewport_scroll_layer_.get(),
+                        proto.inner_viewport_scroll_layer_id(), &layer_tree_);
+  outer_viewport_scroll_layer_ =
+      UpdateAndGetLayer(outer_viewport_scroll_layer_.get(),
+                        proto.outer_viewport_scroll_layer_id(), &layer_tree_);
+
+  LayerSelectionFromProtobuf(&selection_, proto.selection());
+
+  // It is required to create new PropertyTrees before deserializing it.
+  property_trees_ = PropertyTrees();
+  property_trees_.FromProtobuf(proto.property_trees());
+
+  // Forcefully override the sequence number of all layers in the tree to have
+  // a valid sequence number. Changing the sequence number for a layer does not
+  // need a commit, so the value will become out of date for layers that are not
+  // updated for other reasons. All layers that at this point are part of the
+  // layer tree are valid, so it is OK that they have a valid sequence number.
+  int seq_num = property_trees_.sequence_number;
+  LayerTreeHostCommon::CallFunctionForEveryLayer(this, [seq_num](Layer* layer) {
+    layer->set_property_tree_sequence_number(seq_num);
+  });
+
   surface_client_id_ = proto.surface_client_id();
   next_surface_sequence_ = proto.next_surface_sequence();
 }
 
 AnimationHost* LayerTreeHost::animation_host() const {
-  return layer_tree_->animation_host();
+  return layer_tree_.animation_host();
 }
 
 }  // namespace cc