[4/5] Add translated rasterization support for PictureLayerTilingSet & below

cc/layers/picture_layer_impl.cc

Index: cc/layers/picture_layer_impl.cc
diff --git a/cc/layers/picture_layer_impl.cc b/cc/layers/picture_layer_impl.cc
index 03ff4553cfd82e4f9cea5791b38851d9e7386687..39d1a65f60d65b05b19a6f9bf7be9ea0bbed3a6f 100644
--- a/cc/layers/picture_layer_impl.cc
+++ b/cc/layers/picture_layer_impl.cc
@@ -648,12 +648,8 @@ bool PictureLayerImpl::RasterSourceUsesLCDText() const {
 }
 
 void PictureLayerImpl::NotifyTileStateChanged(const Tile* tile) {
-  if (layer_tree_impl()->IsActiveTree()) {
-    gfx::Rect layer_damage_rect = gfx::ScaleToEnclosingRect(
-        tile->content_rect(), 1.f / tile->raster_scales().width(),
-        1.f / tile->raster_scales().height());
-    AddDamageRect(layer_damage_rect);
-  }
+  if (layer_tree_impl()->IsActiveTree())
+    AddDamageRect(tile->enclosing_layer_rect());
   if (tile->draw_info().NeedsRaster()) {
     PictureLayerTiling* tiling =
         tilings_->FindTilingWithScaleKey(tile->contents_scale_key());
@@ -732,8 +728,10 @@ const PictureLayerTiling* PictureLayerImpl::GetPendingOrActiveTwinTiling(
   PictureLayerImpl* twin_layer = GetPendingOrActiveTwinLayer();
   if (!twin_layer)
     return nullptr;
-  return twin_layer->tilings_->FindTilingWithScaleKey(
-      tiling->contents_scale_key());
+  const PictureLayerTiling* twin_tiling = twin_layer->tilings_->FindTilingWithScaleKey(tiling->contents_scale_key());
+  DCHECK(tiling->raster_transform().translation() == gfx::Vector2dF());
+  DCHECK(!twin_tiling || twin_tiling->raster_transform().translation() == gfx::Vector2dF());
+  return twin_tiling;
 }
 
 bool PictureLayerImpl::RequiresHighResToDraw() const {
@@ -894,7 +892,7 @@ PictureLayerTiling* PictureLayerImpl::AddTiling(float contents_scale) {
   DCHECK_GE(contents_scale, MinimumContentsScale());
   DCHECK_LE(contents_scale, MaximumContentsScale());
   DCHECK(raster_source_->HasRecordings());
-  return tilings_->AddTiling(contents_scale, raster_source_);
+  return tilings_->AddTiling(ScaleTranslate2d(contents_scale, gfx::Vector2dF()), raster_source_);
 }
 
 void PictureLayerImpl::RemoveAllTilings() {