Fix bad scaling in TiledLayer

cc/layers/tiled_layer.cc

 // Copyright 2011 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/layers/tiled_layer.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/auto_reset.h"
@@ skipping 444 matching lines @@
 void TiledLayer::UpdateTileTextures(const gfx::Rect& update_rect,
                                     const gfx::Rect& paint_rect,
                                     int left,
                                     int top,
                                     int right,
                                     int bottom,
                                     ResourceUpdateQueue* queue,
                                     const OcclusionTracker<Layer>* occlusion) {
   // The update_rect should be in layer space. So we have to convert the
   // paint_rect from content space to layer space.
-  float width_scale =
-      paint_properties().bounds.width() /
-      static_cast<float>(content_bounds().width());
-  float height_scale =
-      paint_properties().bounds.height() /
-      static_cast<float>(content_bounds().height());
+  float width_scale = 1 / draw_properties().contents_scale_x;
+  float height_scale = 1 / draw_properties().contents_scale_y;
   update_rect_ = gfx::ScaleRect(update_rect, width_scale, height_scale);
 
   // Calling PrepareToUpdate() calls into WebKit to paint, which may have the
   // side effect of disabling compositing, which causes our reference to the
   // texture updater to be deleted.  However, we can't free the memory backing
   // the SkCanvas until the paint finishes, so we grab a local reference here to
   // hold the updater alive until the paint completes.
   scoped_refptr<LayerUpdater> protector(Updater());
-  Updater()->PrepareToUpdate(
-      paint_rect, tiler_->tile_size(), 1.f / width_scale, 1.f / height_scale);
+  Updater()->PrepareToUpdate(content_bounds(),
+                             paint_rect,
+                             tiler_->tile_size(),
+                             1.f / width_scale,
+                             1.f / height_scale);
 
   for (int j = top; j <= bottom; ++j) {
     for (int i = left; i <= right; ++i) {
       UpdatableTile* tile = TileAt(i, j);
       DCHECK(tile);  // Did SetTexturePriorites get skipped?
                      // TODO(enne): This should not ever be null.
       if (!tile)
         continue;
 
       gfx::Rect tile_rect = tiler_->tile_bounds(i, j);
@@ skipping 373 matching lines @@
   gfx::Rect prepaint_rect = visible_content_rect();
   prepaint_rect.Inset(-tiler_->tile_size().width() * kPrepaintColumns,
                       -tiler_->tile_size().height() * kPrepaintRows);
   gfx::Rect content_rect(content_bounds());
   prepaint_rect.Intersect(content_rect);
 
   return prepaint_rect;
 }
 
 }  // namespace cc