cc: Move tiling management out of draw properties calculation.

cc/resources/picture_layer_tiling_set.cc

 // Copyright 2012 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/picture_layer_tiling_set.h"
 
 #include <limits>
 
 namespace cc {
 
@@ skipping 306 matching lines @@
 }
 
 void PictureLayerTilingSet::UpdateTilePriorities(
     WhichTree tree,
     const gfx::Rect& visible_content_rect,
     float layer_contents_scale,
     double current_frame_time_in_seconds) {
   gfx::Rect visible_layer_rect = gfx::ScaleToEnclosingRect(
       visible_content_rect, 1.f / layer_contents_scale);
 
+  float max_layer_contents_scale = layer_contents_scale;

[enne (OOO), 2014/05/28 18:42:20]

You should not need this.  The scale used to be max but is now 1, but this math
should all still work out using that scale.

What is failing, specifically?

[sohanjg, 2014/05/29 13:07:04]

In LayerEvictionTileIterator test, tile->required_for_activation() check fails
for some tiles.
The problem is the PictureLayerImplTest.LayerEvictionTileIterator iterates over
the tiles in a wrong order, the order is again decided the way we pushed the
tiles in the iterator(based on priority), which seems to be different now.
The only reason i found is that previously in
PictureLayerTiling::UpdateTilePriorities the scaling was different than now and
based on that TilePriorities may have been assigned.

Please suggest if there can be any alternate way.

+  for (size_t i = 0; i < this->num_tilings(); ++i) {
+    const PictureLayerTiling* tiling = this->tiling_at(i);
+    max_layer_contents_scale =
+        std::max(max_layer_contents_scale, tiling->contents_scale());
+  }
+
   for (size_t i = 0; i < tilings_.size(); ++i) {
     tilings_[i]->UpdateTilePriorities(tree,
                                       visible_layer_rect,
-                                      layer_contents_scale,
+                                      max_layer_contents_scale,
                                       current_frame_time_in_seconds);
   }
 }
 
 void PictureLayerTilingSet::DidBecomeActive() {
   for (size_t i = 0; i < tilings_.size(); ++i)
     tilings_[i]->DidBecomeActive();
 }
 
 void PictureLayerTilingSet::DidBecomeRecycled() {
   for (size_t i = 0; i < tilings_.size(); ++i)
     tilings_[i]->DidBecomeRecycled();
 }
 
 scoped_ptr<base::Value> PictureLayerTilingSet::AsValue() const {
   scoped_ptr<base::ListValue> state(new base::ListValue());
   for (size_t i = 0; i < tilings_.size(); ++i)
     state->Append(tilings_[i]->AsValue().release());
   return state.PassAs<base::Value>();
 }
 
 size_t PictureLayerTilingSet::GPUMemoryUsageInBytes() const {
   size_t amount = 0;
   for (size_t i = 0; i < tilings_.size(); ++i)
     amount += tilings_[i]->GPUMemoryUsageInBytes();
   return amount;
 }
 
 }  // namespace cc