Refactor RegisterViewportLayers 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 154 matching lines @@
 LayerTreeHost::~LayerTreeHost() {
   // Track when we're inside a main frame to see if compositor is being
   // destroyed midway which causes a crash. crbug.com/654672
   DCHECK(!inside_main_frame_);
   TRACE_EVENT0("cc", "LayerTreeHostInProcess::~LayerTreeHostInProcess");
 
   // Clear any references into the LayerTreeHost.
   mutator_host_->SetMutatorHostClient(nullptr);
 
   // We must clear any pointers into the layer tree prior to destroying it.
-  RegisterViewportLayers(nullptr, nullptr, nullptr, nullptr, nullptr, nullptr);
+  RegisterViewportLayers(ViewportLayers());
 
   if (root_layer_) {
     root_layer_->SetLayerTreeHost(nullptr);
 
     // The root layer must be destroyed before the layer tree. We've made a
     // contract with our animation controllers that the animation_host will
     // outlive them, and we must make good.
     root_layer_ = nullptr;
   }
 
@@ skipping 486 matching lines @@
 }
 
 bool LayerTreeHost::DoUpdateLayers(Layer* root_layer) {
   TRACE_EVENT1("cc", "LayerTreeHostInProcess::DoUpdateLayers",
                "source_frame_number", SourceFrameNumber());
 
   UpdateHudLayer(debug_state_.ShowHudInfo());
 
   Layer* root_scroll =
       PropertyTreeBuilder::FindFirstScrollableLayer(root_layer);
-  Layer* page_scale_layer = page_scale_layer_.get();
+  Layer* page_scale_layer = viewport_layers_.page_scale.get();
   if (!page_scale_layer && root_scroll)
     page_scale_layer = root_scroll->parent();
 
   if (hud_layer_) {
     hud_layer_->PrepareForCalculateDrawProperties(device_viewport_size_,
                                                   device_scale_factor_);
     // The HUD layer is managed outside the layer list sent to LayerTreeHost
     // and needs to have its property tree state set.
     if (settings_.use_layer_lists && root_layer_.get()) {
       hud_layer_->SetTransformTreeIndex(root_layer_->transform_tree_index());
@@ skipping 62 matching lines @@
   if (info->inner_viewport_scroll.layer_id != Layer::INVALID_ID)
     inner_viewport_scroll_delta = info->inner_viewport_scroll.scroll_delta;
 
   if (inner_viewport_scroll_delta.IsZero() && info->page_scale_delta == 1.f &&
       info->elastic_overscroll_delta.IsZero() && !info->top_controls_delta)
     return;
 
   // 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 (inner_viewport_scroll_layer_) {
-    inner_viewport_scroll_layer_->SetScrollOffsetFromImplSide(
+  if (viewport_layers_.inner_viewport_scroll) {
+    viewport_layers_.inner_viewport_scroll->SetScrollOffsetFromImplSide(
         gfx::ScrollOffsetWithDelta(
-            inner_viewport_scroll_layer_->scroll_offset(),
+            viewport_layers_.inner_viewport_scroll->scroll_offset(),
             inner_viewport_scroll_delta));
   }
 
   ApplyPageScaleDeltaFromImplSide(info->page_scale_delta);
   SetElasticOverscrollFromImplSide(elastic_overscroll_ +
                                    info->elastic_overscroll_delta);
   // TODO(ccameron): pass the elastic overscroll here so that input events
   // may be translated appropriately.
   client_->ApplyViewportDeltas(inner_viewport_scroll_delta, gfx::Vector2dF(),
                                info->elastic_overscroll_delta,
@@ skipping 116 matching lines @@
   if (hud_layer_.get())
     hud_layer_->RemoveFromParent();
 
   // Reset gpu rasterization tracking.
   // This flag is sticky until a new tree comes along.
   ResetGpuRasterizationTracking();
 
   SetNeedsFullTreeSync();
 }
 
-void LayerTreeHost::RegisterViewportLayers(
-    scoped_refptr<Layer> overscroll_elasticity_layer,
-    scoped_refptr<Layer> page_scale_layer,
-    scoped_refptr<Layer> inner_viewport_container_layer,
-    scoped_refptr<Layer> outer_viewport_container_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_container_layer_ = inner_viewport_container_layer;
-  outer_viewport_container_layer_ = outer_viewport_container_layer;
-  inner_viewport_scroll_layer_ = inner_viewport_scroll_layer;
-  outer_viewport_scroll_layer_ = outer_viewport_scroll_layer;
+LayerTreeHost::ViewportLayers::ViewportLayers() {}
+
+LayerTreeHost::ViewportLayers::~ViewportLayers() {}
+
+void LayerTreeHost::RegisterViewportLayers(const ViewportLayers& layers) {
+  DCHECK(!layers.inner_viewport_scroll ||
+         layers.inner_viewport_scroll != layers.outer_viewport_scroll);
+  viewport_layers_.overscroll_elasticity = layers.overscroll_elasticity;
+  viewport_layers_.page_scale = layers.page_scale;
+  viewport_layers_.inner_viewport_container = layers.inner_viewport_container;
+  viewport_layers_.outer_viewport_container = layers.outer_viewport_container;
+  viewport_layers_.inner_viewport_scroll = layers.inner_viewport_scroll;
+  viewport_layers_.outer_viewport_scroll = layers.outer_viewport_scroll;
 }
 
 void LayerTreeHost::RegisterSelection(const LayerSelection& selection) {
   if (selection_ == selection)
     return;
 
   selection_ = selection;
   SetNeedsCommit();
 }
 
@@ skipping 235 matching lines @@
   tree_impl->set_event_listener_properties(
       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_) {
+  if (viewport_layers_.page_scale && viewport_layers_.inner_viewport_scroll) {
     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();
+    if (viewport_layers_.overscroll_elasticity)
+      ids.overscroll_elasticity = viewport_layers_.overscroll_elasticity->id();
+    ids.page_scale = viewport_layers_.page_scale->id();
+    if (viewport_layers_.inner_viewport_container)
+      ids.inner_viewport_container =
+          viewport_layers_.inner_viewport_container->id();
+    if (viewport_layers_.outer_viewport_container)
+      ids.outer_viewport_container =
+          viewport_layers_.outer_viewport_container->id();
+    ids.inner_viewport_scroll = viewport_layers_.inner_viewport_scroll->id();
+    if (viewport_layers_.outer_viewport_scroll)
+      ids.outer_viewport_scroll = viewport_layers_.outer_viewport_scroll->id();
     tree_impl->SetViewportLayersFromIds(ids);
-    DCHECK(inner_viewport_scroll_layer_->IsContainerForFixedPositionLayers());
+    DCHECK(viewport_layers_.inner_viewport_scroll
+               ->IsContainerForFixedPositionLayers());
   } else {
     tree_impl->ClearViewportLayers();
   }
 
   tree_impl->RegisterSelection(selection_);
 
   tree_impl->PushPageScaleFromMainThread(
       page_scale_factor_, min_page_scale_factor_, max_page_scale_factor_);
 
   tree_impl->set_browser_controls_shrink_blink_size(
@@ skipping 285 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