cc: Bump up pending tree now tiles order for smoothness mode.

cc/resources/raster_tile_priority_queue.cc

 // Copyright 2014 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/resources/raster_tile_priority_queue.h"
 
 namespace cc {
 
 namespace {
 
@@ skipping 51 matching lines @@
  private:
   TreePriority tree_priority_;
 };
 
 WhichTree HigherPriorityTree(
     TreePriority tree_priority,
     const PictureLayerImpl::LayerRasterTileIterator* active_iterator,
     const PictureLayerImpl::LayerRasterTileIterator* pending_iterator,
     const Tile* shared_tile) {
   switch (tree_priority) {
-    case SMOOTHNESS_TAKES_PRIORITY:
+    case SMOOTHNESS_TAKES_PRIORITY: {
+      const Tile* active_tile = shared_tile ? shared_tile : **active_iterator;
+      const Tile* pending_tile = shared_tile ? shared_tile : **pending_iterator;
+
+      const TilePriority& active_priority = active_tile->priority(ACTIVE_TREE);
+      const TilePriority& pending_priority =
+          pending_tile->priority(PENDING_TREE);
+
+      // If we're down to eventually bin tiles on the active tree, process the
+      // pending tree to allow tiles required for activation to be initialized
+      // when memory policy only allows prepaint.
+      if (active_priority.priority_bin == TilePriority::EVENTUALLY &&
+          pending_priority.priority_bin == TilePriority::NOW) {
+        return PENDING_TREE;
+      }
       return ACTIVE_TREE;
+    }
     case NEW_CONTENT_TAKES_PRIORITY:
       return PENDING_TREE;
     case SAME_PRIORITY_FOR_BOTH_TREES: {
       const Tile* active_tile = shared_tile ? shared_tile : **active_iterator;
       const Tile* pending_tile = shared_tile ? shared_tile : **pending_iterator;
 
       const TilePriority& active_priority = active_tile->priority(ACTIVE_TREE);
       const TilePriority& pending_priority =
           pending_tile->priority(PENDING_TREE);
 
@@ skipping 144 matching lines @@
     return PENDING_TREE;
   if (!pending_iterator)
     return ACTIVE_TREE;
 
   // Now both iterators have tiles, so we have to decide based on tree priority.
   return HigherPriorityTree(
       tree_priority, &active_iterator, &pending_iterator, nullptr);
 }
 
 }  // namespace cc