cc: Simplify the logic for deciding to update tile priorities.

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 "base/debug/trace_event.h"
 #include "cc/animation/animation.h"
 #include "cc/animation/animation_id_provider.h"
 #include "cc/animation/keyframed_animation_curve.h"
@@ skipping 234 matching lines @@
     horiz->SetViewportWithinScrollableArea(scrollable_viewport,
                                            ScrollableSize());
   }
   if (ScrollbarLayerImpl* vertical = root_scroll->vertical_scrollbar_layer()) {
     vertical->set_vertical_adjust(vertical_adjust);
     vertical->SetViewportWithinScrollableArea(scrollable_viewport,
                                               ScrollableSize());
   }
 }
 
-struct UpdateTilePrioritiesForLayer {
-  void operator()(LayerImpl *layer) {
-    layer->UpdateTilePriorities();
-  }
-};
-
-void LayerTreeImpl::UpdateDrawProperties(UpdateDrawPropertiesReason reason) {
+void LayerTreeImpl::UpdateDrawProperties() {
   if (IsActiveTree() && RootScrollLayer() && RootClipLayer())
     UpdateRootScrollLayerSizeDelta();
 
   if (settings().solid_color_scrollbars &&
       IsActiveTree() &&
       RootScrollLayer()) {
     UpdateSolidColorScrollbars();
 
     // The top controls manager is incompatible with the WebKit-created cliprect
     // because it can bring into view a larger amount of content when it
     // hides. It's safe to deactivate the clip rect if no non-overlay scrollbars
     // are present.
     if (RootClipLayer() && layer_tree_host_impl_->top_controls_manager())
       RootClipLayer()->SetMasksToBounds(false);
   }
 
-  if (!needs_update_draw_properties_) {
-    if (reason == UPDATE_ACTIVE_TREE_FOR_DRAW && root_layer())
-      LayerTreeHostCommon::CallFunctionForSubtree<UpdateTilePrioritiesForLayer>(
-          root_layer());
-    return;
-  }
-
   needs_update_draw_properties_ = false;
   render_surface_layer_list_.clear();
 
   // For max_texture_size.
   if (!layer_tree_host_impl_->renderer())
       return;
 
   if (!root_layer())
     return;
 
   if (root_scroll_layer_) {
     root_scroll_layer_->SetImplTransform(ImplTransform());
     // Setting the impl transform re-sets this.
     needs_update_draw_properties_ = false;
   }
 
   {
     TRACE_EVENT1("cc",
                  "LayerTreeImpl::UpdateDrawProperties",
                  "IsActive",
                  IsActiveTree());
+
+    base::TimeTicks frame_time = CurrentFrameTime();
     bool update_tile_priorities =
-        reason == UPDATE_PENDING_TREE ||
-        reason == UPDATE_ACTIVE_TREE_FOR_DRAW;
+        frame_time != frame_time_last_update_tile_priorities_;
+    frame_time_last_update_tile_priorities_ = frame_time;
+
     LayerTreeHostCommon::CalculateDrawProperties(
         root_layer(),
         device_viewport_size(),
         device_scale_factor(),
         total_page_scale_factor(),
         MaxTextureSize(),
         settings().can_use_lcd_text,
         &render_surface_layer_list_,
         update_tile_priorities);
   }
 
   DCHECK(!needs_update_draw_properties_) <<
-      "calcDrawProperties should not set_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)
     ClearRenderSurfacesOnLayerImplRecursive(current->children()[i]);
   current->ClearRenderSurface();
 }
 
 void LayerTreeImpl::ClearRenderSurfaces() {
@@ skipping 43 matching lines @@
 
 void LayerTreeImpl::UnregisterLayer(LayerImpl* layer) {
   DCHECK(LayerById(layer->id()));
   layer_id_map_.erase(layer->id());
 }
 
 void LayerTreeImpl::PushPersistedState(LayerTreeImpl* pending_tree) {
   int id = currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0;
   pending_tree->SetCurrentlyScrollingLayer(
       LayerTreeHostCommon::FindLayerInSubtree(pending_tree->root_layer(), id));
+
+  frame_time_last_update_tile_priorities_ =
+      pending_tree->frame_time_last_update_tile_priorities_;
 }
 
 static void DidBecomeActiveRecursive(LayerImpl* layer) {
   layer->DidBecomeActive();
   for (size_t i = 0; i < layer->children().size(); ++i)
     DidBecomeActiveRecursive(layer->children()[i]);
 }
 
 void LayerTreeImpl::DidBecomeActive() {
   if (root_layer())
@@ skipping 285 matching lines @@
   gfx::Vector2dF original_viewport_size =
       gfx::RectF(root_clip->bounds()).bottom_right() -
       gfx::PointF();
   original_viewport_size.Scale(1 / page_scale_factor());
 
   root_scroll->SetFixedContainerSizeDelta(
       scrollable_viewport_size - original_viewport_size);
 }
 
 }  // namespace cc