cc: Fix missing compositor invalidations during resize

cc/resources/picture_layer_tiling.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.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 
@@ skipping 171 matching lines @@
   DoInvalidate(layer_region, false /* recreate_tiles */);
 }
 
 void PictureLayerTiling::Invalidate(const Region& layer_region) {
   DoInvalidate(layer_region, true /* recreate_tiles */);
 }
 
 void PictureLayerTiling::DoInvalidate(const Region& layer_region,
                                       bool recreate_tiles) {
   std::vector<TileMapKey> new_tile_keys;
+  gfx::Rect expanded_live_tiles_rect(
+      tiling_data_.ExpandRectToTileBoundsWithBorders(live_tiles_rect_));
   for (Region::Iterator iter(layer_region); iter.has_rect(); iter.next()) {
     gfx::Rect layer_rect = iter.rect();
     gfx::Rect content_rect =
         gfx::ScaleToEnclosingRect(layer_rect, contents_scale_);
-    content_rect.Intersect(live_tiles_rect_);
+    // 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;
     bool include_borders = true;
     for (TilingData::Iterator iter(
              &tiling_data_, content_rect, include_borders);
          iter;
          ++iter) {
       TileMapKey key(iter.index());
       TileMap::iterator find = tiles_.find(key);
       if (find == tiles_.end())
@@ skipping 716 matching lines @@
   tiling_->UpdateEvictionCacheIfNeeded(tree_priority_);
   tile_iterator_ = tiling_->eviction_tiles_cache_.begin();
   is_valid_ = true;
   if (tile_iterator_ != tiling_->eviction_tiles_cache_.end() &&
       !(*tile_iterator_)->HasResources()) {
     ++(*this);
   }
 }
 
 }  // namespace cc