Extract subpixel offsets from composited layer transforms when possible.

cc/layers/picture_layer_impl.cc

 // Copyright 2012 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/picture_layer_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 551 matching lines @@
 
   if (!can_have_tilings) {
     RemoveAllTilings();
     return;
   }
 
   // We could do this after doing UpdateTiles, which would avoid doing this for
   // tilings that are going to disappear on the pending tree (if scale changed).
   // But that would also be more complicated, so we just do it here for now.
   if (pending_set) {
+      LOG(ERROR) << "pending_set: " << raster_source_.get();
+
     tilings_->UpdateTilingsToCurrentRasterSourceForActivation(
         raster_source_, pending_set, invalidation_, MinimumContentsScale(),
         MaximumContentsScale());
   } else {
+   
+    LOG(ERROR) << "SetSubpixelOffset: " << raster_source_.get() << ": " << subpixel_offset_.ToString() << ": " << raster_source_->GetSize().ToString();
+    LOG(ERROR) << "DrawsContent: " << DrawsContent();
+    raster_source_->SetSubpixelOffset(subpixel_offset_);
     tilings_->UpdateTilingsToCurrentRasterSourceForCommit(
         raster_source_, invalidation_, MinimumContentsScale(),
         MaximumContentsScale());
   }
 }
 
 void PictureLayerImpl::UpdateCanUseLCDTextAfterCommit() {
   // This function is only allowed to be called after commit, due to it not
   // being smart about sharing tiles and because otherwise it would cause
   // flashes by switching out tiles in place that may be currently on screen.
@@ skipping 669 matching lines @@
 
 bool PictureLayerImpl::IsOnActiveOrPendingTree() const {
   return !layer_tree_impl()->IsRecycleTree();
 }
 
 bool PictureLayerImpl::HasValidTilePriorities() const {
   return IsOnActiveOrPendingTree() && IsDrawnRenderSurfaceLayerListMember();
 }
 
 }  // namespace cc