Blink handle selection handle visibility

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 64 matching lines @@
       max_page_scale_factor_(0),
       device_scale_factor_(1.f),
       painted_device_scale_factor_(1.f),
       elastic_overscroll_(elastic_overscroll),
       layers_(new OwnedLayerImplList),
       viewport_size_invalid_(false),
       needs_update_draw_properties_(true),
       needs_full_tree_sync_(true),
       next_activation_forces_redraw_(false),
       has_ever_been_drawn_(false),
+      handle_visibility_changed_(false),
       have_scroll_event_handlers_(false),
       event_listener_properties_(),
       top_controls_shrink_blink_size_(false),
       top_controls_height_(0),
       bottom_controls_height_(0),
       top_controls_shown_ratio_(top_controls_shown_ratio) {
   property_trees()->is_main_thread = false;
 }
 
 LayerTreeImpl::~LayerTreeImpl() {
@@ skipping 1868 matching lines @@
   bool update_lcd_text = false;
   if (!UpdateDrawProperties(update_lcd_text))
     return NULL;
   FindTouchEventLayerFunctor func = {screen_space_point};
   FindClosestMatchingLayerState state;
   FindClosestMatchingLayer(screen_space_point, layer_list_[0], func, &state);
   return state.closest_match;
 }
 
 void LayerTreeImpl::RegisterSelection(const LayerSelection& selection) {
+  if (selection_ == selection)
+    return;
+
+  handle_visibility_changed_ = true;
   selection_ = selection;
 }
 
+bool LayerTreeImpl::GetAndResetHandleVisibilityChanged() {
+  bool curr_handle_visibility_changed = handle_visibility_changed_;
+  handle_visibility_changed_ = false;
+  return curr_handle_visibility_changed;
+}
+
 static gfx::SelectionBound ComputeViewportSelectionBound(
     const LayerSelectionBound& layer_bound,
     LayerImpl* layer,
     float device_scale_factor) {
   gfx::SelectionBound viewport_bound;
   viewport_bound.set_type(layer_bound.type);
 
   if (!layer || layer_bound.type == gfx::SelectionBound::EMPTY)
     return viewport_bound;
 
@@ skipping 86 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