Refactor SetViewportLayerIds to use a struct instead of 6 values

cc/trees/layer_tree_host.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.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 28 matching lines @@
 #include "cc/layers/heads_up_display_layer_impl.h"
 #include "cc/layers/layer.h"
 #include "cc/layers/painted_scrollbar_layer.h"
 #include "cc/resources/ui_resource_manager.h"
 #include "cc/tiles/frame_viewer_instrumentation.h"
 #include "cc/trees/draw_property_utils.h"
 #include "cc/trees/effect_node.h"
 #include "cc/trees/layer_tree_host_client.h"
 #include "cc/trees/layer_tree_host_common.h"
 #include "cc/trees/layer_tree_host_impl.h"
-#include "cc/trees/layer_tree_impl.h"
 #include "cc/trees/mutator_host.h"
 #include "cc/trees/property_tree_builder.h"
 #include "cc/trees/proxy_main.h"
 #include "cc/trees/single_thread_proxy.h"
 #include "cc/trees/swap_promise_manager.h"
 #include "cc/trees/transform_node.h"
 #include "cc/trees/tree_synchronizer.h"
 #include "ui/gfx/geometry/size_conversions.h"
 #include "ui/gfx/geometry/vector2d_conversions.h"
 
@@ skipping 1107 matching lines @@
       EventListenerClass::kTouchStartOrMove,
       event_listener_properties(EventListenerClass::kTouchStartOrMove));
   tree_impl->set_event_listener_properties(
       EventListenerClass::kMouseWheel,
       event_listener_properties(EventListenerClass::kMouseWheel));
   tree_impl->set_event_listener_properties(
       EventListenerClass::kTouchEndOrCancel,
       event_listener_properties(EventListenerClass::kTouchEndOrCancel));
 
   if (page_scale_layer_ && inner_viewport_scroll_layer_) {
-    tree_impl->SetViewportLayersFromIds(
-        overscroll_elasticity_layer_ ? overscroll_elasticity_layer_->id()
-                                     : Layer::INVALID_ID,
-        page_scale_layer_->id(),
-        inner_viewport_container_layer_ ? inner_viewport_container_layer_->id()
-                                        : Layer::INVALID_ID,
-        outer_viewport_container_layer_ ? outer_viewport_container_layer_->id()
-                                        : Layer::INVALID_ID,
-        inner_viewport_scroll_layer_->id(),
-        outer_viewport_scroll_layer_ ? outer_viewport_scroll_layer_->id()
-                                     : Layer::INVALID_ID);
+    LayerTreeImpl::ViewportLayerIds ids;
+    if (overscroll_elasticity_layer_)
+      ids.overscroll_elasticity = overscroll_elasticity_layer_->id();
+    ids.page_scale = page_scale_layer_->id();
+    if (inner_viewport_container_layer_)
+      ids.inner_viewport_container = inner_viewport_container_layer_->id();
+    if (outer_viewport_container_layer_)
+      ids.outer_viewport_container = outer_viewport_container_layer_->id();
+    ids.inner_viewport_scroll = inner_viewport_scroll_layer_->id();
+    if (outer_viewport_scroll_layer_)
+      ids.outer_viewport_scroll = outer_viewport_scroll_layer_->id();
+    tree_impl->SetViewportLayersFromIds(ids);
     DCHECK(inner_viewport_scroll_layer_->IsContainerForFixedPositionLayers());
   } else {
     tree_impl->ClearViewportLayers();
   }
 
   tree_impl->RegisterSelection(selection_);
 
   tree_impl->PushPageScaleFromMainThread(
       page_scale_factor_, min_page_scale_factor_, max_page_scale_factor_);
 
@@ skipping 286 matching lines @@
 void LayerTreeHost::SetNeedsDisplayOnAllLayers() {
   for (auto* layer : *this)
     layer->SetNeedsDisplay();
 }
 
 void LayerTreeHost::SetHasCopyRequest(bool has_copy_request) {
   has_copy_request_ = has_copy_request;
 }
 
 }  // namespace cc