Update from chromium https://crrev.com/304586

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 {
 
 namespace {
 
 class LargestToSmallestScaleFunctor {
  public:
   bool operator() (PictureLayerTiling* left, PictureLayerTiling* right) {
     return left->contents_scale() > right->contents_scale();
   }
 };
 
 }  // namespace
 
+// static
+scoped_ptr<PictureLayerTilingSet> PictureLayerTilingSet::Create(
+    PictureLayerTilingClient* client) {
+  return make_scoped_ptr(new PictureLayerTilingSet(client));
+}
+
 PictureLayerTilingSet::PictureLayerTilingSet(PictureLayerTilingClient* client)
     : client_(client) {
 }
 
 PictureLayerTilingSet::~PictureLayerTilingSet() {
 }
 
 void PictureLayerTilingSet::SetClient(PictureLayerTilingClient* client) {
   client_ = client;
   for (size_t i = 0; i < tilings_.size(); ++i)
     tilings_[i]->SetClient(client_);
 }
 
 void PictureLayerTilingSet::RemoveTilesInRegion(const Region& region) {
   for (size_t i = 0; i < tilings_.size(); ++i)
     tilings_[i]->RemoveTilesInRegion(region);
 }
 
 bool PictureLayerTilingSet::SyncTilings(const PictureLayerTilingSet& other,
                                         const gfx::Size& new_layer_bounds,
                                         const Region& layer_invalidation,
-                                        float minimum_contents_scale) {
+                                        float minimum_contents_scale,
+                                        RasterSource* raster_source) {
   if (new_layer_bounds.IsEmpty()) {
     RemoveAllTilings();
     return false;
   }
 
   tilings_.reserve(other.tilings_.size());
 
   // Remove any tilings that aren't in |other| or don't meet the minimum.
   for (size_t i = 0; i < tilings_.size(); ++i) {
     float scale = tilings_[i]->contents_scale();
     if (scale >= minimum_contents_scale && !!other.TilingAtScale(scale))
       continue;
     // Swap with the last element and remove it.
     tilings_.swap(tilings_.begin() + i, tilings_.end() - 1);
     tilings_.pop_back();
     --i;
   }
 
   bool have_high_res_tiling = false;
 
   // Add any missing tilings from |other| that meet the minimum.
   for (size_t i = 0; i < other.tilings_.size(); ++i) {
     float contents_scale = other.tilings_[i]->contents_scale();
     if (contents_scale < minimum_contents_scale)
       continue;
     if (PictureLayerTiling* this_tiling = TilingAtScale(contents_scale)) {
       this_tiling->set_resolution(other.tilings_[i]->resolution());
 
-      this_tiling->UpdateTilesToCurrentRasterSource(layer_invalidation,
-                                                    new_layer_bounds);
+      this_tiling->UpdateTilesToCurrentRasterSource(
+          raster_source, layer_invalidation, new_layer_bounds);
       this_tiling->CreateMissingTilesInLiveTilesRect();
       if (this_tiling->resolution() == HIGH_RESOLUTION)
         have_high_res_tiling = true;
 
       DCHECK(this_tiling->tile_size() ==
              client_->CalculateTileSize(this_tiling->tiling_size()))
           << "tile_size: " << this_tiling->tile_size().ToString()
           << " tiling_size: " << this_tiling->tiling_size().ToString()
           << " CalculateTileSize: "
           << client_->CalculateTileSize(this_tiling->tiling_size()).ToString();
@@ skipping 54 matching lines @@
   if (iter == tilings_.end())
     return;
   tilings_.erase(iter);
 }
 
 void PictureLayerTilingSet::RemoveAllTiles() {
   for (size_t i = 0; i < tilings_.size(); ++i)
     tilings_[i]->Reset();
 }
 
+bool PictureLayerTilingSet::UpdateTilePriorities(
+    const gfx::Rect& required_rect_in_layer_space,
+    float ideal_contents_scale,
+    double current_frame_time_in_seconds,
+    const Occlusion& occlusion_in_layer_space,
+    bool can_require_tiles_for_activation) {
+  bool tiling_needs_update = false;
+  // TODO(vmpstr): Check if we have to early out here, or if we can just do it
+  // as part of computing tile priority rects for tilings.
+  for (auto* tiling : tilings_) {
+    if (tiling->NeedsUpdateForFrameAtTimeAndViewport(
+            current_frame_time_in_seconds, required_rect_in_layer_space)) {
+      tiling_needs_update = true;
+      break;
+    }
+  }
+  if (!tiling_needs_update)
+    return false;
+
+  for (auto* tiling : tilings_) {
+    tiling->set_can_require_tiles_for_activation(
+        can_require_tiles_for_activation);
+    tiling->ComputeTilePriorityRects(
+        required_rect_in_layer_space, ideal_contents_scale,
+        current_frame_time_in_seconds, occlusion_in_layer_space);
+  }
+  return true;
+}
+
 PictureLayerTilingSet::CoverageIterator::CoverageIterator(
     const PictureLayerTilingSet* set,
     float contents_scale,
     const gfx::Rect& content_rect,
     float ideal_contents_scale)
     : set_(set),
       contents_scale_(contents_scale),
       ideal_contents_scale_(ideal_contents_scale),
       current_tiling_(-1) {
   missing_region_.Union(content_rect);
@@ skipping 207 matching lines @@
     case LOWER_THAN_LOW_RES:
       range = TilingRange(low_res_range.end, tilings_.size());
       break;
   }
 
   DCHECK_LE(range.start, range.end);
   return range;
 }
 
 }  // namespace cc