cc: Fix missing compositor invalidations during resize

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 d2a732d9eb985e12d15a71405dde751458eb14b2..a3664e770626085c94cf60aa0b25d1b24da3c46a 100644
--- a/cc/resources/picture_layer_tiling.cc
+++ b/cc/resources/picture_layer_tiling.cc
@@ -189,11 +189,15 @@ void PictureLayerTiling::Invalidate(const Region& layer_region) {
 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;