Update from https://crrev.com/305340

cc/layers/picture_layer_impl.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/layers/picture_layer_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 
@@ skipping 107 matching lines @@
   // Twin relationships should never change once established.
   DCHECK_IMPLIES(twin_layer_, twin_layer_ == layer_impl);
   DCHECK_IMPLIES(twin_layer_, layer_impl->twin_layer_ == this);
   // The twin relationship does not need to exist before the first
   // PushPropertiesTo from pending to active layer since before that the active
   // layer can not have a pile or tilings, it has only been created and inserted
   // into the tree at that point.
   twin_layer_ = layer_impl;
   layer_impl->twin_layer_ = this;
 
+  layer_impl->set_is_mask(is_mask_);
   layer_impl->UpdateRasterSource(raster_source_);
 
   DCHECK_IMPLIES(raster_source_->IsSolidColor(), tilings_->num_tilings() == 0);
   // Tilings would be expensive to push, so we swap.
   layer_impl->tilings_.swap(tilings_);
   layer_impl->tilings_->SetClient(layer_impl);
   if (tilings_)
     tilings_->SetClient(this);
 
   // Ensure that the recycle tree doesn't have any unshared tiles.
@@ skipping 740 matching lines @@
       tilings_->AddTiling(contents_scale, raster_source_->GetSize());
 
   DCHECK(raster_source_->HasRecordings());
 
   if (PictureLayerImpl* twin_layer = GetPendingOrActiveTwinLayer())
     twin_layer->SyncTiling(tiling);
 
   return tiling;
 }
 
-void PictureLayerImpl::RemoveTiling(float contents_scale) {
-  if (!tilings_ || tilings_->num_tilings() == 0)
-    return;
-
-  tilings_->RemoveTilingWithScale(contents_scale);
-  if (tilings_->num_tilings() == 0)
-    ResetRasterScale();
-  SanityCheckTilingState();
-}
-
 void PictureLayerImpl::RemoveAllTilings() {
   if (tilings_)
     tilings_->RemoveAllTilings();
   // If there are no tilings, then raster scales are no longer meaningful.
   ResetRasterScale();
 }
 
 void PictureLayerImpl::AddTilingsForRasterScale() {
   // Reset all resolution enums on tilings, we'll be setting new values in this
   // function.
@@ skipping 181 matching lines @@
 void PictureLayerImpl::CleanUpTilingsOnActiveLayer(
     std::vector<PictureLayerTiling*> used_tilings) {
   DCHECK(layer_tree_impl()->IsActiveTree());
   if (tilings_->num_tilings() == 0)
     return;
 
   float min_acceptable_high_res_scale = std::min(
       raster_contents_scale_, ideal_contents_scale_);
   float max_acceptable_high_res_scale = std::max(
       raster_contents_scale_, ideal_contents_scale_);
-  float twin_low_res_scale = 0.f;
 
   PictureLayerImpl* twin = GetPendingOrActiveTwinLayer();
   if (twin && twin->CanHaveTilings()) {
     min_acceptable_high_res_scale = std::min(
         min_acceptable_high_res_scale,
         std::min(twin->raster_contents_scale_, twin->ideal_contents_scale_));
     max_acceptable_high_res_scale = std::max(
         max_acceptable_high_res_scale,
         std::max(twin->raster_contents_scale_, twin->ideal_contents_scale_));
-
-    // TODO(danakj): Remove the tilings_ check when we create them in the
-    // constructor.
-    if (twin->tilings_) {
-      PictureLayerTiling* tiling =
-          twin->tilings_->FindTilingWithResolution(LOW_RESOLUTION);
-      if (tiling)
-        twin_low_res_scale = tiling->contents_scale();
-    }
   }
 
-  // TODO(vmpstr): Put this logic into PictureLayerTilingSet.
-  std::vector<PictureLayerTiling*> to_remove;
-  for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
-    PictureLayerTiling* tiling = tilings_->tiling_at(i);
+  PictureLayerTilingSet* twin_set = twin ? twin->tilings_.get() : nullptr;
+  PictureLayerImpl* recycled_twin = GetRecycledTwinLayer();
+  PictureLayerTilingSet* recycled_twin_set =
+      recycled_twin ? recycled_twin->tilings_.get() : nullptr;
 
-    // Keep multiple high resolution tilings even if not used to help
-    // activate earlier at non-ideal resolutions.
-    if (tiling->contents_scale() >= min_acceptable_high_res_scale &&
-        tiling->contents_scale() <= max_acceptable_high_res_scale)
-      continue;
+  tilings_->CleanUpTilings(min_acceptable_high_res_scale,
+                           max_acceptable_high_res_scale, used_tilings,
+                           layer_tree_impl()->create_low_res_tiling(), twin_set,
+                           recycled_twin_set);
 
-    // Keep low resolution tilings, if the layer should have them.
-    if (layer_tree_impl()->create_low_res_tiling()) {
-      if (tiling->resolution() == LOW_RESOLUTION ||
-          tiling->contents_scale() == twin_low_res_scale)
-        continue;
-    }
+  if (twin_set && twin_set->num_tilings() == 0)
+    twin->ResetRasterScale();
 
-    // Don't remove tilings that are being used (and thus would cause a flash.)
-    if (std::find(used_tilings.begin(), used_tilings.end(), tiling) !=
-        used_tilings.end())
-      continue;
-
-    to_remove.push_back(tiling);
-  }
-
-  if (to_remove.empty())
-    return;
-
-  PictureLayerImpl* recycled_twin = GetRecycledTwinLayer();
-  // Remove tilings on this tree and the twin tree.
-  for (size_t i = 0; i < to_remove.size(); ++i) {
-    const PictureLayerTiling* twin_tiling =
-        GetPendingOrActiveTwinTiling(to_remove[i]);
-    // Only remove tilings from the twin layer if they have
-    // NON_IDEAL_RESOLUTION.
-    if (twin_tiling && twin_tiling->resolution() == NON_IDEAL_RESOLUTION)
-      twin->RemoveTiling(to_remove[i]->contents_scale());
-    // Remove the tiling from the recycle tree. Note that we ignore resolution,
-    // since we don't need to maintain high/low res on the recycle tree.
-    if (recycled_twin)
-      recycled_twin->RemoveTiling(to_remove[i]->contents_scale());
-    // TODO(enne): temporary sanity CHECK for http://crbug.com/358350
-    CHECK_NE(HIGH_RESOLUTION, to_remove[i]->resolution());
-    tilings_->Remove(to_remove[i]);
-  }
+  if (recycled_twin_set && recycled_twin_set->num_tilings() == 0)
+    recycled_twin->ResetRasterScale();
 
   DCHECK_GT(tilings_->num_tilings(), 0u);
   SanityCheckTilingState();
 }
 
 float PictureLayerImpl::MinimumContentsScale() const {
   float setting_min = layer_tree_impl()->settings().minimum_contents_scale;
 
   // If the contents scale is less than 1 / width (also for height),
   // then it will end up having less than one pixel of content in that
@@ skipping 497 matching lines @@
       PictureLayerTilingSet::TilingRange tiling_range = CurrentTilingRange();
       size_t current_tiling_range_offset = current_tiling_ - tiling_range.start;
       return tiling_range.end - 1 - current_tiling_range_offset;
     }
   }
   NOTREACHED();
   return 0;
 }
 
 }  // namespace cc