cc: Throttle tile priority updates to once a frame.

cc/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/layer_tree_impl.h"
 
 #include "base/debug/trace_event.h"
 #include "cc/layer_tree_host_common.h"
 #include "cc/layer_tree_host_impl.h"
 #include "ui/gfx/vector2d_conversions.h"
@@ skipping 103 matching lines @@
   gfx::Vector2dF max_scroll = gfx::Rect(ScrollableSize()).bottom_right() -
       gfx::RectF(view_bounds).bottom_right();
 
   // The viewport may be larger than the contents in some cases, such as
   // having a vertical scrollbar but no horizontal overflow.
   max_scroll.ClampToMin(gfx::Vector2dF());
 
   root_scroll_layer_->setMaxScrollOffset(gfx::ToFlooredVector2d(max_scroll));
 }
 
-void LayerTreeImpl::UpdateDrawProperties() {
-  if (!needs_update_draw_properties_)
+struct UpdateTilePrioritiesForLayer {
+  void operator()(LayerImpl *layer) {
+    layer->updateTilePriorities();
+  }
+};
+
+void LayerTreeImpl::UpdateDrawProperties(UpdateDrawPropertiesReason reason) {
+  if (!needs_update_draw_properties_) {
+    if (reason == UPDATE_ACTIVE_TREE_FOR_DRAW && RootLayer())
+      LayerTreeHostCommon::callFunctionForSubtree<UpdateTilePrioritiesForLayer>(
+          RootLayer());
     return;
+  }
 
   needs_update_draw_properties_ = false;
   render_surface_layer_list_.clear();
 
   // For maxTextureSize.
   if (!layer_tree_host_impl_->renderer())
       return;
 
   if (!RootLayer())
     return;
 
   if (root_scroll_layer_) {
     root_scroll_layer_->setImplTransform(
         layer_tree_host_impl_->implTransform());
     // Setting the impl transform re-sets this.
     needs_update_draw_properties_ = false;
   }
 
   {
     TRACE_EVENT1("cc", "LayerTreeImpl::UpdateDrawProperties", "IsActive", IsActiveTree());
+    bool update_tile_priorities =
+        reason == UPDATE_PENDING_TREE ||
+        reason == UPDATE_ACTIVE_TREE_FOR_DRAW;
     LayerTreeHostCommon::calculateDrawProperties(
         RootLayer(),
         device_viewport_size(),
         device_scale_factor(),
         pinch_zoom_viewport().page_scale_factor(),
         MaxTextureSize(),
         settings().canUseLCDText,
-        render_surface_layer_list_);
+        render_surface_layer_list_,
+        update_tile_priorities);
   }
 
   DCHECK(!needs_update_draw_properties_) <<
       "calcDrawProperties should not set_needs_update_draw_properties()";
 }
 
 static void ClearRenderSurfacesOnLayerImplRecursive(LayerImpl* current)
 {
     DCHECK(current);
     for (size_t i = 0; i < current->children().size(); ++i)
@@ skipping 176 matching lines @@
 
 AnimationRegistrar* LayerTreeImpl::animationRegistrar() const {
   return layer_tree_host_impl_->animationRegistrar();
 }
 
 const PinchZoomViewport& LayerTreeImpl::pinch_zoom_viewport() const {
   return layer_tree_host_impl_->pinchZoomViewport();
 }
 
 } // namespace cc