Revert "Revert 253606 "Revert 251238 "cc: Clean up iterator template to ...""

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 <algorithm>
 #include <stack>
 #include <string>
 
@@ skipping 869 matching lines @@
   surface_memory_placeholder_->SetTextureManager(
       contents_texture_manager_.get());
   surface_memory_placeholder_->set_request_priority(
       PriorityCalculator::RenderSurfacePriority());
   surface_memory_placeholder_->SetToSelfManagedMemoryPlaceholder(
       surface_memory_bytes);
 }
 
 void LayerTreeHost::SetPrioritiesForLayers(
     const RenderSurfaceLayerList& update_list) {
+  typedef LayerIterator<Layer,
+                        RenderSurfaceLayerList,
+                        RenderSurface,
+                        LayerIteratorActions::FrontToBack> LayerIteratorType;
+
   PriorityCalculator calculator;
-  typedef LayerIterator<Layer> LayerIteratorType;
   LayerIteratorType end = LayerIteratorType::End(&update_list);
   for (LayerIteratorType it = LayerIteratorType::Begin(&update_list);
        it != end;
        ++it) {
     if (it.represents_itself()) {
       it->SetTexturePriorities(calculator);
     } else if (it.represents_target_render_surface()) {
       if (it->mask_layer())
         it->mask_layer()->SetTexturePriorities(calculator);
       if (it->replica_layer() && it->replica_layer()->mask_layer())
@@ skipping 76 matching lines @@
     *did_paint_content |= replica_mask_layer->Update(queue, NULL);
     *need_more_updates |= replica_mask_layer->NeedMoreUpdates();
   }
 }
 
 void LayerTreeHost::PaintLayerContents(
     const RenderSurfaceLayerList& render_surface_layer_list,
     ResourceUpdateQueue* queue,
     bool* did_paint_content,
     bool* need_more_updates) {
+  // Use FrontToBack to allow for testing occlusion and performing culling
+  // during the tree walk.
+  typedef LayerIterator<Layer,
+                        RenderSurfaceLayerList,
+                        RenderSurface,
+                        LayerIteratorActions::FrontToBack> LayerIteratorType;
+
   bool record_metrics_for_frame =
       settings_.show_overdraw_in_tracing &&
       base::debug::TraceLog::GetInstance() &&
       base::debug::TraceLog::GetInstance()->IsEnabled();
   OcclusionTracker occlusion_tracker(
       root_layer_->render_surface()->content_rect(), record_metrics_for_frame);
   occlusion_tracker.set_minimum_tracking_size(
       settings_.minimum_occlusion_tracking_size);
 
   PrioritizeTextures(render_surface_layer_list,
                      occlusion_tracker.overdraw_metrics());
 
   in_paint_layer_contents_ = true;
 
-  // Iterates front-to-back to allow for testing occlusion and performing
-  // culling during the tree walk.
-  typedef LayerIterator<Layer> LayerIteratorType;
   LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list);
   for (LayerIteratorType it =
            LayerIteratorType::Begin(&render_surface_layer_list);
        it != end;
        ++it) {
     occlusion_tracker.EnterLayer(it);
 
     if (it.represents_target_render_surface()) {
       PaintMasksForRenderSurface(
           *it, queue, did_paint_content, need_more_updates);
@@ skipping 297 matching lines @@
   swap_promise_list_.push_back(swap_promise.Pass());
 }
 
 void LayerTreeHost::BreakSwapPromises(SwapPromise::DidNotSwapReason reason) {
   for (size_t i = 0; i < swap_promise_list_.size(); i++)
     swap_promise_list_[i]->DidNotSwap(reason);
   swap_promise_list_.clear();
 }
 
 }  // namespace cc