Remove parts of //cc we aren't using

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
deleted file mode 100644
index 171a8cb15242a259dc8e6e8cadcd0e5e1bbd83ba..0000000000000000000000000000000000000000
--- a/cc/resources/picture_layer_tiling.cc
+++ /dev/null
@@ -1,1073 +0,0 @@
-// 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.h"
-
-#include <algorithm>
-#include <cmath>
-#include <limits>
-#include <set>
-
-#include "base/logging.h"
-#include "base/trace_event/trace_event.h"
-#include "base/trace_event/trace_event_argument.h"
-#include "cc/base/math_util.h"
-#include "cc/resources/tile.h"
-#include "cc/resources/tile_priority.h"
-#include "ui/gfx/geometry/point_conversions.h"
-#include "ui/gfx/geometry/rect_conversions.h"
-#include "ui/gfx/geometry/safe_integer_conversions.h"
-#include "ui/gfx/geometry/size_conversions.h"
-
-namespace cc {
-namespace {
-
-const float kSoonBorderDistanceViewportPercentage = 0.15f;
-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,
-    PictureLayerTilingClient* client,
-    size_t max_tiles_for_interest_area,
-    float skewport_target_time_in_seconds,
-    int skewport_extrapolation_limit_in_content_pixels)
-    : max_tiles_for_interest_area_(max_tiles_for_interest_area),
-      skewport_target_time_in_seconds_(skewport_target_time_in_seconds),
-      skewport_extrapolation_limit_in_content_pixels_(
-          skewport_extrapolation_limit_in_content_pixels),
-      contents_scale_(contents_scale),
-      client_(client),
-      raster_source_(raster_source),
-      resolution_(NON_IDEAL_RESOLUTION),
-      tiling_data_(gfx::Size(), gfx::Size(), kBorderTexels),
-      can_require_tiles_for_activation_(false),
-      current_content_to_screen_scale_(0.f),
-      has_visible_rect_tiles_(false),
-      has_skewport_rect_tiles_(false),
-      has_soon_border_rect_tiles_(false),
-      has_eventually_rect_tiles_(false) {
-  DCHECK(!raster_source->IsSolidColor());
-  gfx::Size content_bounds = gfx::ToCeiledSize(
-      gfx::ScaleSize(raster_source_->GetSize(), contents_scale));
-  gfx::Size tile_size = client_->CalculateTileSize(content_bounds);
-
-  DCHECK(!gfx::ToFlooredSize(gfx::ScaleSize(raster_source_->GetSize(),
-                                            contents_scale)).IsEmpty())
-      << "Tiling created with scale too small as contents become empty."
-      << " Layer bounds: " << raster_source_->GetSize().ToString()
-      << " Contents scale: " << contents_scale;
-
-  tiling_data_.SetTilingSize(content_bounds);
-  tiling_data_.SetMaxTextureSize(tile_size);
-}
-
-PictureLayerTiling::~PictureLayerTiling() {
-  for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it)
-    it->second->set_shared(false);
-}
-
-// static
-float PictureLayerTiling::CalculateSoonBorderDistance(
-    const gfx::Rect& visible_rect_in_content_space,
-    float content_to_screen_scale) {
-  float max_dimension = std::max(visible_rect_in_content_space.width(),
-                                 visible_rect_in_content_space.height());
-  return std::min(
-      kMaxSoonBorderDistanceInScreenPixels / content_to_screen_scale,
-      max_dimension * kSoonBorderDistanceViewportPercentage);
-}
-
-Tile* PictureLayerTiling::CreateTile(int i,
-                                     int j,
-                                     const PictureLayerTiling* twin_tiling,
-                                     PictureLayerTiling* recycled_twin) {
-  // 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());
-
-  gfx::Rect paint_rect = tiling_data_.TileBoundsWithBorder(i, j);
-  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),
-      tile_i_(0),
-      tile_j_(0),
-      left_(0),
-      top_(0),
-      right_(-1),
-      bottom_(-1) {
-}
-
-PictureLayerTiling::CoverageIterator::CoverageIterator(
-    const PictureLayerTiling* tiling,
-    float dest_scale,
-    const gfx::Rect& dest_rect)
-    : tiling_(tiling),
-      dest_rect_(dest_rect),
-      dest_to_content_scale_(0),
-      current_tile_(NULL),
-      tile_i_(0),
-      tile_j_(0),
-      left_(0),
-      top_(0),
-      right_(-1),
-      bottom_(-1) {
-  DCHECK(tiling_);
-  if (dest_rect_.IsEmpty())
-    return;
-
-  dest_to_content_scale_ = tiling_->contents_scale_ / dest_scale;
-
-  gfx::Rect content_rect =
-      gfx::ScaleToEnclosingRect(dest_rect_,
-                                dest_to_content_scale_,
-                                dest_to_content_scale_);
-  // IndexFromSrcCoord clamps to valid tile ranges, so it's necessary to
-  // check for non-intersection first.
-  content_rect.Intersect(gfx::Rect(tiling_->tiling_size()));
-  if (content_rect.IsEmpty())
-    return;
-
-  left_ = tiling_->tiling_data_.TileXIndexFromSrcCoord(content_rect.x());
-  top_ = tiling_->tiling_data_.TileYIndexFromSrcCoord(content_rect.y());
-  right_ = tiling_->tiling_data_.TileXIndexFromSrcCoord(
-      content_rect.right() - 1);
-  bottom_ = tiling_->tiling_data_.TileYIndexFromSrcCoord(
-      content_rect.bottom() - 1);
-
-  tile_i_ = left_ - 1;
-  tile_j_ = top_;
-  ++(*this);
-}
-
-PictureLayerTiling::CoverageIterator::~CoverageIterator() {
-}
-
-PictureLayerTiling::CoverageIterator&
-PictureLayerTiling::CoverageIterator::operator++() {
-  if (tile_j_ > bottom_)
-    return *this;
-
-  bool first_time = tile_i_ < left_;
-  bool new_row = false;
-  tile_i_++;
-  if (tile_i_ > right_) {
-    tile_i_ = left_;
-    tile_j_++;
-    new_row = true;
-    if (tile_j_ > bottom_) {
-      current_tile_ = NULL;
-      return *this;
-    }
-  }
-
-  current_tile_ = tiling_->TileAt(tile_i_, tile_j_);
-
-  // Calculate the current geometry rect.  Due to floating point rounding
-  // and ToEnclosingRect, tiles might overlap in destination space on the
-  // edges.
-  gfx::Rect last_geometry_rect = current_geometry_rect_;
-
-  gfx::Rect content_rect = tiling_->tiling_data_.TileBounds(tile_i_, tile_j_);
-
-  current_geometry_rect_ =
-      gfx::ScaleToEnclosingRect(content_rect,
-                                1 / dest_to_content_scale_,
-                                1 / dest_to_content_scale_);
-
-  current_geometry_rect_.Intersect(dest_rect_);
-
-  if (first_time)
-    return *this;
-
-  // Iteration happens left->right, top->bottom.  Running off the bottom-right
-  // edge is handled by the intersection above with dest_rect_.  Here we make
-  // sure that the new current geometry rect doesn't overlap with the last.
-  int min_left;
-  int min_top;
-  if (new_row) {
-    min_left = dest_rect_.x();
-    min_top = last_geometry_rect.bottom();
-  } else {
-    min_left = last_geometry_rect.right();
-    min_top = last_geometry_rect.y();
-  }
-
-  int inset_left = std::max(0, min_left - current_geometry_rect_.x());
-  int inset_top = std::max(0, min_top - current_geometry_rect_.y());
-  current_geometry_rect_.Inset(inset_left, inset_top, 0, 0);
-
-  if (!new_row) {
-    DCHECK_EQ(last_geometry_rect.right(), current_geometry_rect_.x());
-    DCHECK_EQ(last_geometry_rect.bottom(), current_geometry_rect_.bottom());
-    DCHECK_EQ(last_geometry_rect.y(), current_geometry_rect_.y());
-  }
-
-  return *this;
-}
-
-gfx::Rect PictureLayerTiling::CoverageIterator::geometry_rect() const {
-  return current_geometry_rect_;
-}
-
-gfx::RectF PictureLayerTiling::CoverageIterator::texture_rect() const {
-  gfx::PointF tex_origin =
-      tiling_->tiling_data_.TileBoundsWithBorder(tile_i_, tile_j_).origin();
-
-  // Convert from dest space => content space => texture space.
-  gfx::RectF texture_rect(current_geometry_rect_);
-  texture_rect.Scale(dest_to_content_scale_,
-                     dest_to_content_scale_);
-  texture_rect.Intersect(gfx::Rect(tiling_->tiling_size()));
-  if (texture_rect.IsEmpty())
-    return texture_rect;
-  texture_rect.Offset(-tex_origin.OffsetFromOrigin());
-
-  return texture_rect;
-}
-
-bool PictureLayerTiling::RemoveTileAt(int i,
-                                      int j,
-                                      PictureLayerTiling* recycled_twin) {
-  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();
-}
-
-gfx::Rect PictureLayerTiling::ComputeSkewport(
-    double current_frame_time_in_seconds,
-    const gfx::Rect& visible_rect_in_content_space) const {
-  gfx::Rect skewport = visible_rect_in_content_space;
-  if (skewport.IsEmpty())
-    return skewport;
-
-  if (visible_rect_history_[1].frame_time_in_seconds == 0.0)
-    return skewport;
-
-  double time_delta = current_frame_time_in_seconds -
-                      visible_rect_history_[1].frame_time_in_seconds;
-  if (time_delta == 0.0)
-    return skewport;
-
-  double extrapolation_multiplier =
-      skewport_target_time_in_seconds_ / time_delta;
-
-  int old_x = visible_rect_history_[1].visible_rect_in_content_space.x();
-  int old_y = visible_rect_history_[1].visible_rect_in_content_space.y();
-  int old_right =
-      visible_rect_history_[1].visible_rect_in_content_space.right();
-  int old_bottom =
-      visible_rect_history_[1].visible_rect_in_content_space.bottom();
-
-  int new_x = visible_rect_in_content_space.x();
-  int new_y = visible_rect_in_content_space.y();
-  int new_right = visible_rect_in_content_space.right();
-  int new_bottom = visible_rect_in_content_space.bottom();
-
-  // Compute the maximum skewport based on
-  // |skewport_extrapolation_limit_in_content_pixels_|.
-  gfx::Rect max_skewport = skewport;
-  max_skewport.Inset(-skewport_extrapolation_limit_in_content_pixels_,
-                     -skewport_extrapolation_limit_in_content_pixels_);
-
-  // Inset the skewport by the needed adjustment.
-  skewport.Inset(extrapolation_multiplier * (new_x - old_x),
-                 extrapolation_multiplier * (new_y - old_y),
-                 extrapolation_multiplier * (old_right - new_right),
-                 extrapolation_multiplier * (old_bottom - new_bottom));
-
-  // Ensure that visible rect is contained in the skewport.
-  skewport.Union(visible_rect_in_content_space);
-
-  // Clip the skewport to |max_skewport|. This needs to happen after the
-  // union in case intersecting would have left the empty rect.
-  skewport.Intersect(max_skewport);
-
-  return skewport;
-}
-
-bool PictureLayerTiling::ComputeTilePriorityRects(
-    const gfx::Rect& viewport_in_layer_space,
-    float ideal_contents_scale,
-    double current_frame_time_in_seconds,
-    const Occlusion& occlusion_in_layer_space) {
-  if (!NeedsUpdateForFrameAtTimeAndViewport(current_frame_time_in_seconds,
-                                            viewport_in_layer_space)) {
-    // This should never be zero for the purposes of has_ever_been_updated().
-    DCHECK_NE(current_frame_time_in_seconds, 0.0);
-    return false;
-  }
-
-  gfx::Rect visible_rect_in_content_space =
-      gfx::ScaleToEnclosingRect(viewport_in_layer_space, contents_scale_);
-
-  if (tiling_size().IsEmpty()) {
-    UpdateVisibleRectHistory(current_frame_time_in_seconds,
-                             visible_rect_in_content_space);
-    last_viewport_in_layer_space_ = viewport_in_layer_space;
-    return false;
-  }
-
-  // Calculate the skewport.
-  gfx::Rect skewport = ComputeSkewport(current_frame_time_in_seconds,
-                                       visible_rect_in_content_space);
-  DCHECK(skewport.Contains(visible_rect_in_content_space));
-
-  // Calculate the eventually/live tiles rect.
-  gfx::Size tile_size = tiling_data_.max_texture_size();
-  int64 eventually_rect_area =
-      max_tiles_for_interest_area_ * tile_size.width() * tile_size.height();
-
-  gfx::Rect eventually_rect =
-      ExpandRectEquallyToAreaBoundedBy(visible_rect_in_content_space,
-                                       eventually_rect_area,
-                                       gfx::Rect(tiling_size()),
-                                       &expansion_cache_);
-
-  DCHECK(eventually_rect.IsEmpty() ||
-         gfx::Rect(tiling_size()).Contains(eventually_rect))
-      << "tiling_size: " << tiling_size().ToString()
-      << " eventually_rect: " << eventually_rect.ToString();
-
-  // Calculate the soon border rect.
-  float content_to_screen_scale = ideal_contents_scale / contents_scale_;
-  gfx::Rect soon_border_rect = visible_rect_in_content_space;
-  float border = CalculateSoonBorderDistance(visible_rect_in_content_space,
-                                             content_to_screen_scale);
-  soon_border_rect.Inset(-border, -border, -border, -border);
-
-  UpdateVisibleRectHistory(current_frame_time_in_seconds,
-                           visible_rect_in_content_space);
-  last_viewport_in_layer_space_ = viewport_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(
-    float content_to_screen_scale,
-    const gfx::Rect& visible_rect_in_content_space,
-    const gfx::Rect& skewport,
-    const gfx::Rect& soon_border_rect,
-    const gfx::Rect& eventually_rect,
-    const Occlusion& occlusion_in_layer_space) {
-  current_visible_rect_ = visible_rect_in_content_space;
-  current_skewport_rect_ = skewport;
-  current_soon_border_rect_ = soon_border_rect;
-  current_eventually_rect_ = eventually_rect;
-  current_occlusion_in_layer_space_ = occlusion_in_layer_space;
-  current_content_to_screen_scale_ = content_to_screen_scale;
-
-  gfx::Rect tiling_rect(tiling_size());
-  has_visible_rect_tiles_ = tiling_rect.Intersects(current_visible_rect_);
-  has_skewport_rect_tiles_ = tiling_rect.Intersects(current_skewport_rect_);
-  has_soon_border_rect_tiles_ =
-      tiling_rect.Intersects(current_soon_border_rect_);
-  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) {
-    if (!it->second.get())
-      continue;
-    DCHECK(it->first.first < tiling_data_.num_tiles_x())
-        << this << " " << it->first.first << "," << it->first.second
-        << " num_tiles_x " << tiling_data_.num_tiles_x() << " live_tiles_rect "
-        << live_tiles_rect_.ToString();
-    DCHECK(it->first.second < tiling_data_.num_tiles_y())
-        << this << " " << it->first.first << "," << it->first.second
-        << " num_tiles_y " << tiling_data_.num_tiles_y() << " live_tiles_rect "
-        << live_tiles_rect_.ToString();
-    DCHECK(tiling_data_.TileBounds(it->first.first, it->first.second)
-               .Intersects(live_tiles_rect_))
-        << this << " " << it->first.first << "," << it->first.second
-        << " tile bounds "
-        << tiling_data_.TileBounds(it->first.first, it->first.second).ToString()
-        << " live_tiles_rect " << live_tiles_rect_.ToString();
-    DCHECK_IMPLIES(is_on_recycle_tree, it->second->is_shared());
-  }
-#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);
-}
-
-TilePriority PictureLayerTiling::ComputePriorityForTile(
-    const Tile* tile) const {
-  // TODO(vmpstr): See if this can be moved to iterators.
-  TilePriority::PriorityBin max_tile_priority_bin =
-      client_->GetMaxTilePriorityBin();
-
-  DCHECK_EQ(TileAt(tile->tiling_i_index(), tile->tiling_j_index()), tile);
-  gfx::Rect tile_bounds =
-      tiling_data_.TileBounds(tile->tiling_i_index(), tile->tiling_j_index());
-
-  if (max_tile_priority_bin <= TilePriority::NOW &&
-      current_visible_rect_.Intersects(tile_bounds)) {
-    return TilePriority(resolution_, TilePriority::NOW, 0);
-  }
-
-  DCHECK_GT(current_content_to_screen_scale_, 0.f);
-  float distance_to_visible =
-      current_visible_rect_.ManhattanInternalDistance(tile_bounds) *
-      current_content_to_screen_scale_;
-
-  if (max_tile_priority_bin <= TilePriority::SOON &&
-      (current_soon_border_rect_.Intersects(tile_bounds) ||
-       current_skewport_rect_.Intersects(tile_bounds))) {
-    return TilePriority(resolution_, TilePriority::SOON, distance_to_visible);
-  }
-
-  return TilePriority(resolution_, TilePriority::EVENTUALLY,
-                      distance_to_visible);
-}
-
-void PictureLayerTiling::GetAllTilesAndPrioritiesForTracing(
-    std::map<const Tile*, TilePriority>* tile_map) const {
-  const PictureLayerTiling* twin_tiling =
-      client_->GetPendingOrActiveTwinTiling(this);
-  for (const auto& tile_pair : tiles_) {
-    const Tile* tile = tile_pair.second.get();
-    const TilePriority& priority = ComputePriorityForTile(tile);
-    const TilePriority& twin_priority =
-        twin_tiling ? twin_tiling->ComputePriorityForTile(tile)
-                    : TilePriority();
-
-    // Store combined priority.
-    (*tile_map)[tile] = TilePriority(priority, twin_priority);
-  }
-}
-
-void PictureLayerTiling::AsValueInto(
-    base::trace_event::TracedValue* state) const {
-  state->SetInteger("num_tiles", tiles_.size());
-  state->SetDouble("content_scale", contents_scale_);
-  MathUtil::AddToTracedValue("visible_rect", current_visible_rect_, state);
-  MathUtil::AddToTracedValue("skewport_rect", current_skewport_rect_, state);
-  MathUtil::AddToTracedValue("soon_rect", current_soon_border_rect_, state);
-  MathUtil::AddToTracedValue("eventually_rect", current_eventually_rect_,
-                             state);
-  MathUtil::AddToTracedValue("tiling_size", tiling_size(), state);
-}
-
-size_t PictureLayerTiling::GPUMemoryUsageInBytes() const {
-  size_t amount = 0;
-  for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it) {
-    const Tile* tile = it->second.get();
-    amount += tile->GPUMemoryUsageInBytes();
-  }
-  return amount;
-}
-
-PictureLayerTiling::RectExpansionCache::RectExpansionCache()
-  : previous_target(0) {
-}
-
-namespace {
-
-// This struct represents an event at which the expending rect intersects
-// one of its boundaries.  4 intersection events will occur during expansion.
-struct EdgeEvent {
-  enum { BOTTOM, TOP, LEFT, RIGHT } edge;
-  int* num_edges;
-  int distance;
-};
-
-// Compute the delta to expand from edges to cover target_area.
-int ComputeExpansionDelta(int num_x_edges, int num_y_edges,
-                          int width, int height,
-                          int64 target_area) {
-  // Compute coefficients for the quadratic equation:
-  //   a*x^2 + b*x + c = 0
-  int a = num_y_edges * num_x_edges;
-  int b = num_y_edges * width + num_x_edges * height;
-  int64 c = static_cast<int64>(width) * height - target_area;
-
-  // Compute the delta for our edges using the quadratic equation.
-  int delta =
-      (a == 0) ? -c / b : (-b + static_cast<int>(std::sqrt(
-                                    static_cast<int64>(b) * b - 4.0 * a * c))) /
-                              (2 * a);
-  return std::max(0, delta);
-}
-
-}  // namespace
-
-gfx::Rect PictureLayerTiling::ExpandRectEquallyToAreaBoundedBy(
-    const gfx::Rect& starting_rect,
-    int64 target_area,
-    const gfx::Rect& bounding_rect,
-    RectExpansionCache* cache) {
-  if (starting_rect.IsEmpty())
-    return starting_rect;
-
-  if (cache &&
-      cache->previous_start == starting_rect &&
-      cache->previous_bounds == bounding_rect &&
-      cache->previous_target == target_area)
-    return cache->previous_result;
-
-  if (cache) {
-    cache->previous_start = starting_rect;
-    cache->previous_bounds = bounding_rect;
-    cache->previous_target = target_area;
-  }
-
-  DCHECK(!bounding_rect.IsEmpty());
-  DCHECK_GT(target_area, 0);
-
-  // Expand the starting rect to cover target_area, if it is smaller than it.
-  int delta = ComputeExpansionDelta(
-      2, 2, starting_rect.width(), starting_rect.height(), target_area);
-  gfx::Rect expanded_starting_rect = starting_rect;
-  if (delta > 0)
-    expanded_starting_rect.Inset(-delta, -delta);
-
-  gfx::Rect rect = IntersectRects(expanded_starting_rect, bounding_rect);
-  if (rect.IsEmpty()) {
-    // The starting_rect and bounding_rect are far away.
-    if (cache)
-      cache->previous_result = rect;
-    return rect;
-  }
-  if (delta >= 0 && rect == expanded_starting_rect) {
-    // The starting rect already covers the entire bounding_rect and isn't too
-    // large for the target_area.
-    if (cache)
-      cache->previous_result = rect;
-    return rect;
-  }
-
-  // Continue to expand/shrink rect to let it cover target_area.
-
-  // These values will be updated by the loop and uses as the output.
-  int origin_x = rect.x();
-  int origin_y = rect.y();
-  int width = rect.width();
-  int height = rect.height();
-
-  // In the beginning we will consider 2 edges in each dimension.
-  int num_y_edges = 2;
-  int num_x_edges = 2;
-
-  // Create an event list.
-  EdgeEvent events[] = {
-    { EdgeEvent::BOTTOM, &num_y_edges, rect.y() - bounding_rect.y() },
-    { EdgeEvent::TOP, &num_y_edges, bounding_rect.bottom() - rect.bottom() },
-    { EdgeEvent::LEFT, &num_x_edges, rect.x() - bounding_rect.x() },
-    { EdgeEvent::RIGHT, &num_x_edges, bounding_rect.right() - rect.right() }
-  };
-
-  // Sort the events by distance (closest first).
-  if (events[0].distance > events[1].distance) std::swap(events[0], events[1]);
-  if (events[2].distance > events[3].distance) std::swap(events[2], events[3]);
-  if (events[0].distance > events[2].distance) std::swap(events[0], events[2]);
-  if (events[1].distance > events[3].distance) std::swap(events[1], events[3]);
-  if (events[1].distance > events[2].distance) std::swap(events[1], events[2]);
-
-  for (int event_index = 0; event_index < 4; event_index++) {
-    const EdgeEvent& event = events[event_index];
-
-    int delta = ComputeExpansionDelta(
-        num_x_edges, num_y_edges, width, height, target_area);
-
-    // Clamp delta to our event distance.
-    if (delta > event.distance)
-      delta = event.distance;
-
-    // Adjust the edge count for this kind of edge.
-    --*event.num_edges;
-
-    // Apply the delta to the edges and edge events.
-    for (int i = event_index; i < 4; i++) {
-      switch (events[i].edge) {
-        case EdgeEvent::BOTTOM:
-            origin_y -= delta;
-            height += delta;
-            break;
-        case EdgeEvent::TOP:
-            height += delta;
-            break;
-        case EdgeEvent::LEFT:
-            origin_x -= delta;
-            width += delta;
-            break;
-        case EdgeEvent::RIGHT:
-            width += delta;
-            break;
-      }
-      events[i].distance -= delta;
-    }
-
-    // If our delta is less then our event distance, we're done.
-    if (delta < event.distance)
-      break;
-  }
-
-  gfx::Rect result(origin_x, origin_y, width, height);
-  if (cache)
-    cache->previous_result = result;
-  return result;
-}
-
-}  // namespace cc