(not for review) nwayover

cc/tiles/tile_manager.cc

Index: cc/tiles/tile_manager.cc
diff --git a/cc/tiles/tile_manager.cc b/cc/tiles/tile_manager.cc
index b9d3ab7fd1535260af4c358a69181603cdf974ec..d84c44ac2dd58a09405545e8fe1af72014e0874a 100644
--- a/cc/tiles/tile_manager.cc
+++ b/cc/tiles/tile_manager.cc
@@ -24,6 +24,7 @@
 #include "cc/tiles/tile.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 
+#include "ui/gfx/transform.h"
 namespace cc {
 namespace {
 
@@ -276,7 +277,6 @@ void TileManager::CleanUpReleasedTiles() {
     DCHECK(tiles_.find(tile->id()) != tiles_.end());
     tiles_.erase(tile->id());
 
-    image_decode_controller_.SubtractLayerUsedCount(tile->layer_id());
     delete tile;
   }
   released_tiles_.swap(tiles_to_retain);
@@ -681,8 +681,20 @@ scoped_refptr<RasterTask> TileManager::CreateRasterTask(
   prioritized_tile.raster_source()->GetDiscardableImagesInRect(
       tile->enclosing_layer_rect(), &images);
   for (const auto& image : images) {
-    decode_tasks.push_back(image_decode_controller_.GetTaskForImage(
-        image, tile->layer_id(), prepare_tiles_count_));
+    // The images we get have a matrix representing the ctm we would use if we
+    // were to rasterize at scale 1. However, we need to rasterize at
+    // contents_scale, so we should adjust the matrix before querying the
+    // controller.
+    SkMatrix matrix = image.matrix;
+    matrix.preScale(tile->contents_scale(), tile->contents_scale());
+    const PositionImage& scaled_image = PositionImage(
+        image.image, image.image_rect, matrix, image.filter_quality);
+
+    scoped_refptr<ImageDecodeTask> task =
+        image_decode_controller_.GetTaskForImage(scaled_image,
+                                                 prepare_tiles_count_);
+    if (task)
+      decode_tasks.push_back(task);
   }
 
   return make_scoped_refptr(new RasterTaskImpl(
@@ -763,7 +775,6 @@ ScopedTilePtr TileManager::CreateTile(const Tile::CreateInfo& info,
   DCHECK(tiles_.find(tile->id()) == tiles_.end());
 
   tiles_[tile->id()] = tile.get();
-  image_decode_controller_.AddLayerUsedCount(tile->layer_id());
   return tile;
 }