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

cc/tiles/picture_layer_tiling_set.cc

Index: cc/tiles/picture_layer_tiling_set.cc
diff --git a/cc/tiles/picture_layer_tiling_set.cc b/cc/tiles/picture_layer_tiling_set.cc
index 55b86ae95a4bab317e978d2945f9b64a97d923db..ba69c611a906efdc1d3617ca554af3ccb21a3ff7 100644
--- a/cc/tiles/picture_layer_tiling_set.cc
+++ b/cc/tiles/picture_layer_tiling_set.cc
@@ -83,11 +83,16 @@ void PictureLayerTilingSet::CopyTilingsAndPropertiesFromPendingTwin(
 
   bool tiling_sort_required = false;
   for (const auto& pending_twin_tiling : pending_twin_set->tilings_) {
+    ScaleTranslate2d raster_transform = pending_twin_tiling->raster_transform();
     PictureLayerTiling* this_tiling =
         FindTilingWithScaleKey(pending_twin_tiling->contents_scale_key());
+    if (this_tiling && this_tiling->raster_transform() != raster_transform) {

[enne (OOO), 2017/01/03 22:53:53]

This could use some unit testing too.

[trchen, 2017/03/28 21:44:01]

Done.

+      Remove(this_tiling);
+      this_tiling = nullptr;
+    }
     if (!this_tiling) {
       std::unique_ptr<PictureLayerTiling> new_tiling(new PictureLayerTiling(
-          tree_, pending_twin_tiling->raster_scales(), raster_source_, client_,
+          tree_, raster_transform, raster_source_, client_,
           kMaxSoonBorderDistanceInScreenPixels, max_preraster_distance_));
       tilings_.push_back(std::move(new_tiling));
       this_tiling = tilings_.back().get();
@@ -270,22 +275,20 @@ void PictureLayerTilingSet::MarkAllTilingsNonIdeal() {
 }
 
 PictureLayerTiling* PictureLayerTilingSet::AddTiling(
-    float contents_scale_key,
+    const ScaleTranslate2d& raster_transform,
     scoped_refptr<RasterSource> raster_source) {
   if (!raster_source_)
     raster_source_ = raster_source;
 
 #if DCHECK_IS_ON()
   for (size_t i = 0; i < tilings_.size(); ++i) {
-    DCHECK_NE(tilings_[i]->contents_scale_key(), contents_scale_key);
+    DCHECK_NE(tilings_[i]->contents_scale_key(), raster_transform.scale());
     DCHECK_EQ(tilings_[i]->raster_source(), raster_source.get());
   }
 #endif  // DCHECK_IS_ON()
 
-  gfx::SizeF raster_scales(contents_scale_key,
-                           contents_scale_key / aspect_ratio_);
   tilings_.push_back(base::MakeUnique<PictureLayerTiling>(
-      tree_, raster_scales, raster_source, client_,
+      tree_, raster_transform, raster_source, client_,
       kMaxSoonBorderDistanceInScreenPixels, max_preraster_distance_));
   PictureLayerTiling* appended = tilings_.back().get();
   state_since_last_tile_priority_update_.added_tilings = true;
@@ -383,8 +386,7 @@ float PictureLayerTilingSet::GetMaximumContentsScale() const {
   if (tilings_.empty())
     return 0.f;
   // The first tiling has the largest contents scale.
-  return std::max(tilings_[0]->raster_scales().width(),
-                  tilings_[0]->raster_scales().height());
+  return tilings_[0]->raster_transform().scale();
 }
 
 bool PictureLayerTilingSet::TilingsNeedUpdate(