cc: Remove tile sharing from tilings.

cc/resources/picture_layer_tiling.cc

Index: cc/resources/picture_layer_tiling.cc
diff --git a/cc/resources/picture_layer_tiling.cc b/cc/resources/picture_layer_tiling.cc
index 171a8cb15242a259dc8e6e8cadcd0e5e1bbd83ba..8ba2fe1d6ca3b134e64b55a61b56e62560566004 100644
--- a/cc/resources/picture_layer_tiling.cc
+++ b/cc/resources/picture_layer_tiling.cc
@@ -28,19 +28,6 @@ const float kMaxSoonBorderDistanceInScreenPixels = 312.f;
 
 }  // namespace
 
-scoped_ptr<PictureLayerTiling> PictureLayerTiling::Create(
-    float contents_scale,
-    scoped_refptr<RasterSource> raster_source,
-    PictureLayerTilingClient* client,
-    size_t max_tiles_for_interest_area,
-    float skewport_target_time_in_seconds,
-    int skewport_extrapolation_limit_in_content_pixels) {
-  return make_scoped_ptr(new PictureLayerTiling(
-      contents_scale, raster_source, client, max_tiles_for_interest_area,
-      skewport_target_time_in_seconds,
-      skewport_extrapolation_limit_in_content_pixels));
-}
-
 PictureLayerTiling::PictureLayerTiling(
     float contents_scale,
     scoped_refptr<RasterSource> raster_source,
@@ -79,8 +66,6 @@ PictureLayerTiling::PictureLayerTiling(
 }
 
 PictureLayerTiling::~PictureLayerTiling() {
-  for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it)
-    it->second->set_shared(false);
 }
 
 // static
@@ -94,13 +79,14 @@ float PictureLayerTiling::CalculateSoonBorderDistance(
       max_dimension * kSoonBorderDistanceViewportPercentage);
 }
 
-Tile* PictureLayerTiling::CreateTile(int i,
-                                     int j,
-                                     const PictureLayerTiling* twin_tiling,
-                                     PictureLayerTiling* recycled_twin) {
+bool PictureLayerTiling::TilingMatchesTileIndecies(
+    const PictureLayerTiling* twin) const {
+  return tiling_data_.max_texture_size() ==
+         twin->tiling_data_.max_texture_size();
+}
+
+Tile* PictureLayerTiling::CreateTile(int i, int j) {
   // Can't have both a (pending or active) twin and a recycled twin tiling.
-  DCHECK_IMPLIES(twin_tiling, !recycled_twin);
-  DCHECK_IMPLIES(recycled_twin, !twin_tiling);
   TileMapKey key(i, j);
   DCHECK(tiles_.find(key) == tiles_.end());
 
@@ -108,258 +94,16 @@ Tile* PictureLayerTiling::CreateTile(int i,
   gfx::Rect tile_rect = paint_rect;
   tile_rect.set_size(tiling_data_.max_texture_size());
 
-  // Check our twin for a valid tile.
-  if (twin_tiling &&
-      tiling_data_.max_texture_size() ==
-      twin_tiling->tiling_data_.max_texture_size()) {
-    if (Tile* candidate_tile = twin_tiling->TileAt(i, j)) {
-      gfx::Rect rect =
-          gfx::ScaleToEnclosingRect(paint_rect, 1.0f / contents_scale_);
-      const Region* invalidation = client_->GetPendingInvalidation();
-      if (!invalidation || !invalidation->Intersects(rect)) {
-        DCHECK(!candidate_tile->is_shared());
-        DCHECK_EQ(i, candidate_tile->tiling_i_index());
-        DCHECK_EQ(j, candidate_tile->tiling_j_index());
-        candidate_tile->set_shared(true);
-        tiles_[key] = candidate_tile;
-        return candidate_tile;
-      }
-    }
-  }
-
   if (!raster_source_->CoversRect(tile_rect, contents_scale_))
     return nullptr;
 
   // Create a new tile because our twin didn't have a valid one.
   scoped_refptr<Tile> tile = client_->CreateTile(contents_scale_, tile_rect);
-  DCHECK(!tile->is_shared());
   tile->set_tiling_index(i, j);
   tiles_[key] = tile;
-
-  if (recycled_twin) {
-    DCHECK(recycled_twin->tiles_.find(key) == recycled_twin->tiles_.end());
-    // Do what recycled_twin->CreateTile() would do.
-    tile->set_shared(true);
-    recycled_twin->tiles_[key] = tile;
-  }
   return tile.get();
 }
 
-void PictureLayerTiling::CreateMissingTilesInLiveTilesRect() {
-  const PictureLayerTiling* twin_tiling =
-      client_->GetPendingOrActiveTwinTiling(this);
-  // There is no recycled twin during commit from the main thread which is when
-  // this occurs.
-  PictureLayerTiling* null_recycled_twin = nullptr;
-  DCHECK_EQ(null_recycled_twin, client_->GetRecycledTwinTiling(this));
-  bool include_borders = false;
-  for (TilingData::Iterator iter(
-           &tiling_data_, live_tiles_rect_, include_borders);
-       iter;
-       ++iter) {
-    TileMapKey key = iter.index();
-    TileMap::iterator find = tiles_.find(key);
-    if (find != tiles_.end())
-      continue;
-    CreateTile(key.first, key.second, twin_tiling, null_recycled_twin);
-  }
-
-  VerifyLiveTilesRect(false);
-}
-
-void PictureLayerTiling::CloneTilesAndPropertiesFrom(
-    const PictureLayerTiling& twin_tiling) {
-  DCHECK_EQ(&twin_tiling, client_->GetPendingOrActiveTwinTiling(this));
-
-  SetRasterSourceAndResize(twin_tiling.raster_source_);
-  DCHECK_EQ(twin_tiling.contents_scale_, contents_scale_);
-  DCHECK_EQ(twin_tiling.raster_source_, raster_source_);
-  DCHECK_EQ(twin_tiling.tile_size().ToString(), tile_size().ToString());
-
-  resolution_ = twin_tiling.resolution_;
-
-  SetLiveTilesRect(twin_tiling.live_tiles_rect());
-
-  // Recreate unshared tiles.
-  std::vector<TileMapKey> to_remove;
-  for (const auto& tile_map_pair : tiles_) {
-    TileMapKey key = tile_map_pair.first;
-    Tile* tile = tile_map_pair.second.get();
-    if (!tile->is_shared())
-      to_remove.push_back(key);
-  }
-  // The recycled twin does not exist since there is a pending twin (which is
-  // |twin_tiling|).
-  PictureLayerTiling* null_recycled_twin = nullptr;
-  DCHECK_EQ(null_recycled_twin, client_->GetRecycledTwinTiling(this));
-  for (const auto& key : to_remove) {
-    RemoveTileAt(key.first, key.second, null_recycled_twin);
-    CreateTile(key.first, key.second, &twin_tiling, null_recycled_twin);
-  }
-
-  // Create any missing tiles from the |twin_tiling|.
-  for (const auto& tile_map_pair : twin_tiling.tiles_) {
-    TileMapKey key = tile_map_pair.first;
-    Tile* tile = tile_map_pair.second.get();
-    if (!tile->is_shared())
-      CreateTile(key.first, key.second, &twin_tiling, null_recycled_twin);
-  }
-
-  DCHECK_EQ(twin_tiling.tiles_.size(), tiles_.size());
-#if DCHECK_IS_ON()
-  for (const auto& tile_map_pair : tiles_)
-    DCHECK(tile_map_pair.second->is_shared());
-  VerifyLiveTilesRect(false);
-#endif
-
-  UpdateTilePriorityRects(twin_tiling.current_content_to_screen_scale_,
-                          twin_tiling.current_visible_rect_,
-                          twin_tiling.current_skewport_rect_,
-                          twin_tiling.current_soon_border_rect_,
-                          twin_tiling.current_eventually_rect_,
-                          twin_tiling.current_occlusion_in_layer_space_);
-}
-
-void PictureLayerTiling::SetRasterSourceAndResize(
-    scoped_refptr<RasterSource> raster_source) {
-  DCHECK(!raster_source->IsSolidColor());
-  gfx::Size old_layer_bounds = raster_source_->GetSize();
-  raster_source_.swap(raster_source);
-  gfx::Size new_layer_bounds = raster_source_->GetSize();
-  gfx::Size content_bounds =
-      gfx::ToCeiledSize(gfx::ScaleSize(new_layer_bounds, contents_scale_));
-  gfx::Size tile_size = client_->CalculateTileSize(content_bounds);
-
-  if (tile_size != tiling_data_.max_texture_size()) {
-    tiling_data_.SetTilingSize(content_bounds);
-    tiling_data_.SetMaxTextureSize(tile_size);
-    // When the tile size changes, the TilingData positions no longer work
-    // as valid keys to the TileMap, so just drop all tiles and clear the live
-    // tiles rect.
-    Reset();
-    return;
-  }
-
-  if (old_layer_bounds == new_layer_bounds)
-    return;
-
-  // The SetLiveTilesRect() method would drop tiles outside the new bounds,
-  // but may do so incorrectly if resizing the tiling causes the number of
-  // tiles in the tiling_data_ to change.
-  gfx::Rect content_rect(content_bounds);
-  int before_left = tiling_data_.TileXIndexFromSrcCoord(live_tiles_rect_.x());
-  int before_top = tiling_data_.TileYIndexFromSrcCoord(live_tiles_rect_.y());
-  int before_right =
-      tiling_data_.TileXIndexFromSrcCoord(live_tiles_rect_.right() - 1);
-  int before_bottom =
-      tiling_data_.TileYIndexFromSrcCoord(live_tiles_rect_.bottom() - 1);
-
-  // The live_tiles_rect_ is clamped to stay within the tiling size as we
-  // change it.
-  live_tiles_rect_.Intersect(content_rect);
-  tiling_data_.SetTilingSize(content_bounds);
-
-  int after_right = -1;
-  int after_bottom = -1;
-  if (!live_tiles_rect_.IsEmpty()) {
-    after_right =
-        tiling_data_.TileXIndexFromSrcCoord(live_tiles_rect_.right() - 1);
-    after_bottom =
-        tiling_data_.TileYIndexFromSrcCoord(live_tiles_rect_.bottom() - 1);
-  }
-
-  // There is no recycled twin since this is run on the pending tiling
-  // during commit, and on the active tree during activate.
-  PictureLayerTiling* null_recycled_twin = nullptr;
-  DCHECK_EQ(null_recycled_twin, client_->GetRecycledTwinTiling(this));
-
-  // Drop tiles outside the new layer bounds if the layer shrank.
-  for (int i = after_right + 1; i <= before_right; ++i) {
-    for (int j = before_top; j <= before_bottom; ++j)
-      RemoveTileAt(i, j, null_recycled_twin);
-  }
-  for (int i = before_left; i <= after_right; ++i) {
-    for (int j = after_bottom + 1; j <= before_bottom; ++j)
-      RemoveTileAt(i, j, null_recycled_twin);
-  }
-
-  // If the layer grew, the live_tiles_rect_ is not changed, but a new row
-  // and/or column of tiles may now exist inside the same live_tiles_rect_.
-  const PictureLayerTiling* twin_tiling =
-      client_->GetPendingOrActiveTwinTiling(this);
-  if (after_right > before_right) {
-    DCHECK_EQ(after_right, before_right + 1);
-    for (int j = before_top; j <= after_bottom; ++j)
-      CreateTile(after_right, j, twin_tiling, null_recycled_twin);
-  }
-  if (after_bottom > before_bottom) {
-    DCHECK_EQ(after_bottom, before_bottom + 1);
-    for (int i = before_left; i <= before_right; ++i)
-      CreateTile(i, after_bottom, twin_tiling, null_recycled_twin);
-  }
-}
-
-void PictureLayerTiling::Invalidate(const Region& layer_invalidation) {
-  if (live_tiles_rect_.IsEmpty())
-    return;
-  std::vector<TileMapKey> new_tile_keys;
-  gfx::Rect expanded_live_tiles_rect =
-      tiling_data_.ExpandRectIgnoringBordersToTileBounds(live_tiles_rect_);
-  for (Region::Iterator iter(layer_invalidation); iter.has_rect();
-       iter.next()) {
-    gfx::Rect layer_rect = iter.rect();
-    gfx::Rect content_rect =
-        gfx::ScaleToEnclosingRect(layer_rect, contents_scale_);
-    // Consider tiles inside the live tiles rect even if only their border
-    // pixels intersect the invalidation. But don't consider tiles outside
-    // the live tiles rect with the same conditions, as they won't exist.
-    int border_pixels = tiling_data_.border_texels();
-    content_rect.Inset(-border_pixels, -border_pixels);
-    // Avoid needless work by not bothering to invalidate where there aren't
-    // tiles.
-    content_rect.Intersect(expanded_live_tiles_rect);
-    if (content_rect.IsEmpty())
-      continue;
-    // Since the content_rect includes border pixels already, don't include
-    // borders when iterating to avoid double counting them.
-    bool include_borders = false;
-    for (TilingData::Iterator iter(
-             &tiling_data_, content_rect, include_borders);
-         iter;
-         ++iter) {
-      // There is no recycled twin for the pending tree during commit, or for
-      // the active tree during activation.
-      PictureLayerTiling* null_recycled_twin = nullptr;
-      DCHECK_EQ(null_recycled_twin, client_->GetRecycledTwinTiling(this));
-      if (RemoveTileAt(iter.index_x(), iter.index_y(), null_recycled_twin))
-        new_tile_keys.push_back(iter.index());
-    }
-  }
-
-  if (!new_tile_keys.empty()) {
-    // During commit from the main thread, invalidations can never be shared
-    // with the active tree since the active tree has different content there.
-    // And when invalidating an active-tree tiling, it means there was no
-    // pending tiling to clone from.
-    const PictureLayerTiling* null_twin_tiling = nullptr;
-    PictureLayerTiling* null_recycled_twin = nullptr;
-    DCHECK_EQ(null_recycled_twin, client_->GetRecycledTwinTiling(this));
-    for (size_t i = 0; i < new_tile_keys.size(); ++i) {
-      CreateTile(new_tile_keys[i].first, new_tile_keys[i].second,
-                 null_twin_tiling, null_recycled_twin);
-    }
-  }
-}
-
-void PictureLayerTiling::SetRasterSourceOnTiles() {
-  // Shared (ie. non-invalidated) tiles on the pending tree are updated to use
-  // the new raster source. When this raster source is activated, the raster
-  // source will remain valid for shared tiles in the active tree.
-  for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it)
-    it->second->set_raster_source(raster_source_);
-  VerifyLiveTilesRect(false);
-}
-
 PictureLayerTiling::CoverageIterator::CoverageIterator()
     : tiling_(NULL),
       current_tile_(NULL),
@@ -499,29 +243,16 @@ gfx::RectF PictureLayerTiling::CoverageIterator::texture_rect() const {
   return texture_rect;
 }
 
-bool PictureLayerTiling::RemoveTileAt(int i,
-                                      int j,
-                                      PictureLayerTiling* recycled_twin) {
+bool PictureLayerTiling::RemoveTileAt(int i, int j) {
   TileMap::iterator found = tiles_.find(TileMapKey(i, j));
   if (found == tiles_.end())
     return false;
-  found->second->set_shared(false);
   tiles_.erase(found);
-  if (recycled_twin) {
-    // Recycled twin does not also have a recycled twin, so pass null.
-    recycled_twin->RemoveTileAt(i, j, nullptr);
-  }
   return true;
 }
 
 void PictureLayerTiling::Reset() {
   live_tiles_rect_ = gfx::Rect();
-  PictureLayerTiling* recycled_twin = client_->GetRecycledTwinTiling(this);
-  for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it) {
-    it->second->set_shared(false);
-    if (recycled_twin)
-      recycled_twin->RemoveTileAt(it->first.first, it->first.second, nullptr);
-  }
   tiles_.clear();
 }
 
@@ -631,14 +362,14 @@ bool PictureLayerTiling::ComputeTilePriorityRects(
                            visible_rect_in_content_space);
   last_viewport_in_layer_space_ = viewport_in_layer_space;
 
+  SetTilePriorityRects(content_to_screen_scale, visible_rect_in_content_space,
+                       skewport, soon_border_rect, eventually_rect,
+                       occlusion_in_layer_space);
   SetLiveTilesRect(eventually_rect);
-  UpdateTilePriorityRects(
-      content_to_screen_scale, visible_rect_in_content_space, skewport,
-      soon_border_rect, eventually_rect, occlusion_in_layer_space);
   return true;
 }
 
-void PictureLayerTiling::UpdateTilePriorityRects(
+void PictureLayerTiling::SetTilePriorityRects(
     float content_to_screen_scale,
     const gfx::Rect& visible_rect_in_content_space,
     const gfx::Rect& skewport,
@@ -660,47 +391,6 @@ void PictureLayerTiling::UpdateTilePriorityRects(
   has_eventually_rect_tiles_ = tiling_rect.Intersects(current_eventually_rect_);
 }
 
-void PictureLayerTiling::SetLiveTilesRect(
-    const gfx::Rect& new_live_tiles_rect) {
-  DCHECK(new_live_tiles_rect.IsEmpty() ||
-         gfx::Rect(tiling_size()).Contains(new_live_tiles_rect))
-      << "tiling_size: " << tiling_size().ToString()
-      << " new_live_tiles_rect: " << new_live_tiles_rect.ToString();
-  if (live_tiles_rect_ == new_live_tiles_rect)
-    return;
-
-  PictureLayerTiling* recycled_twin = client_->GetRecycledTwinTiling(this);
-
-  // Iterate to delete all tiles outside of our new live_tiles rect.
-  for (TilingData::DifferenceIterator iter(&tiling_data_,
-                                           live_tiles_rect_,
-                                           new_live_tiles_rect);
-       iter;
-       ++iter) {
-    RemoveTileAt(iter.index_x(), iter.index_y(), recycled_twin);
-  }
-
-  const PictureLayerTiling* twin_tiling =
-      client_->GetPendingOrActiveTwinTiling(this);
-
-  // Iterate to allocate new tiles for all regions with newly exposed area.
-  for (TilingData::DifferenceIterator iter(&tiling_data_,
-                                           new_live_tiles_rect,
-                                           live_tiles_rect_);
-       iter;
-       ++iter) {
-    TileMapKey key(iter.index());
-    CreateTile(key.first, key.second, twin_tiling, recycled_twin);
-  }
-
-  live_tiles_rect_ = new_live_tiles_rect;
-  VerifyLiveTilesRect(false);
-  if (recycled_twin) {
-    recycled_twin->live_tiles_rect_ = live_tiles_rect_;
-    recycled_twin->VerifyLiveTilesRect(true);
-  }
-}
-
 void PictureLayerTiling::VerifyLiveTilesRect(bool is_on_recycle_tree) const {
 #if DCHECK_IS_ON()
   for (auto it = tiles_.begin(); it != tiles_.end(); ++it) {
@@ -725,131 +415,13 @@ void PictureLayerTiling::VerifyLiveTilesRect(bool is_on_recycle_tree) const {
 #endif
 }
 
-bool PictureLayerTiling::IsTileOccluded(const Tile* tile) const {
-  DCHECK(tile);
-
-  if (!current_occlusion_in_layer_space_.HasOcclusion())
-    return false;
-
-  gfx::Rect tile_query_rect =
-      gfx::IntersectRects(tile->content_rect(), current_visible_rect_);
-
-  // Explicitly check if the tile is outside the viewport. If so, we need to
-  // return false, since occlusion for this tile is unknown.
-  // TODO(vmpstr): Since the current visible rect is really a viewport in
-  // layer space, we should probably clip tile query rect to tiling bounds
-  // or live tiles rect.
-  if (tile_query_rect.IsEmpty())
-    return false;
-
-  if (contents_scale_ != 1.f) {
-    tile_query_rect =
-        gfx::ScaleToEnclosingRect(tile_query_rect, 1.0f / contents_scale_);
-  }
-
-  return current_occlusion_in_layer_space_.IsOccluded(tile_query_rect);
-}
-
-bool PictureLayerTiling::IsTileRequiredForActivationIfVisible(
-    const Tile* tile) const {
-  DCHECK_EQ(PENDING_TREE, client_->GetTree());
-
-  // This function assumes that the tile is visible (i.e. in the viewport).  The
-  // caller needs to make sure that this condition is met to ensure we don't
-  // block activation on tiles outside of the viewport.
-
-  // If we are not allowed to mark tiles as required for activation, then don't
-  // do it.
-  if (!can_require_tiles_for_activation_)
-    return false;
-
-  if (resolution_ != HIGH_RESOLUTION)
-    return false;
-
-  if (IsTileOccluded(tile))
-    return false;
-
-  if (client_->RequiresHighResToDraw())
-    return true;
-
-  const PictureLayerTiling* twin_tiling =
-      client_->GetPendingOrActiveTwinTiling(this);
-  if (!twin_tiling)
-    return true;
-
-  if (twin_tiling->raster_source()->GetSize() != raster_source()->GetSize())
-    return true;
-
-  if (twin_tiling->current_visible_rect_ != current_visible_rect_)
-    return true;
-
-  Tile* twin_tile =
-      twin_tiling->TileAt(tile->tiling_i_index(), tile->tiling_j_index());
-  // If twin tile is missing, it might not have a recording, so we don't need
-  // this tile to be required for activation.
-  if (!twin_tile)
-    return false;
-
-  return true;
-}
-
-bool PictureLayerTiling::IsTileRequiredForDrawIfVisible(
-    const Tile* tile) const {
-  DCHECK_EQ(ACTIVE_TREE, client_->GetTree());
-
-  // This function assumes that the tile is visible (i.e. in the viewport).
-
-  if (resolution_ != HIGH_RESOLUTION)
-    return false;
-
-  if (IsTileOccluded(tile))
-    return false;
-
-  return true;
-}
-
 void PictureLayerTiling::UpdateTileAndTwinPriority(Tile* tile) const {
   WhichTree tree = client_->GetTree();
   WhichTree twin_tree = tree == ACTIVE_TREE ? PENDING_TREE : ACTIVE_TREE;
-
   tile->SetPriority(tree, ComputePriorityForTile(tile));
-  UpdateRequiredStateForTile(tile, tree);
-
-  const PictureLayerTiling* twin_tiling =
-      client_->GetPendingOrActiveTwinTiling(this);
-  if (!tile->is_shared() || !twin_tiling) {
-    tile->SetPriority(twin_tree, TilePriority());
-    tile->set_is_occluded(twin_tree, false);
-    if (twin_tree == PENDING_TREE)
-      tile->set_required_for_activation(false);
-    else
-      tile->set_required_for_draw(false);
-    return;
-  }
-
-  tile->SetPriority(twin_tree, twin_tiling->ComputePriorityForTile(tile));
-  twin_tiling->UpdateRequiredStateForTile(tile, twin_tree);
-}
-
-void PictureLayerTiling::UpdateRequiredStateForTile(Tile* tile,
-                                                    WhichTree tree) const {
-  if (tile->priority(tree).priority_bin == TilePriority::NOW) {
-    if (tree == PENDING_TREE) {
-      tile->set_required_for_activation(
-          IsTileRequiredForActivationIfVisible(tile));
-    } else {
-      tile->set_required_for_draw(IsTileRequiredForDrawIfVisible(tile));
-    }
-    tile->set_is_occluded(tree, IsTileOccluded(tile));
-    return;
-  }
-
-  // Non-NOW bin tiles are not required or occluded.
-  if (tree == PENDING_TREE)
-    tile->set_required_for_activation(false);
-  else
-    tile->set_required_for_draw(false);
-  tile->set_is_occluded(tree, false);
+  tile->SetPriority(twin_tree, TilePriority());
+  tile->set_required_for_activation(IsTileRequiredForActivation(tile));
+  tile->set_required_for_draw(IsTileRequiredForDraw(tile));
 }
 
 TilePriority PictureLayerTiling::ComputePriorityForTile(
@@ -867,6 +439,11 @@ TilePriority PictureLayerTiling::ComputePriorityForTile(
     return TilePriority(resolution_, TilePriority::NOW, 0);
   }
 
+  if (max_tile_priority_bin <= TilePriority::SOON &&
+      pending_visible_rect().Intersects(tile_bounds)) {
+    return TilePriority(resolution_, TilePriority::SOON, 0);
+  }
+
   DCHECK_GT(current_content_to_screen_scale_, 0.f);
   float distance_to_visible =
       current_visible_rect_.ManhattanInternalDistance(tile_bounds) *