Extract subpixel offsets from composited layer transforms when possible.

cc/playback/raster_source.cc

Index: cc/playback/raster_source.cc
diff --git a/cc/playback/raster_source.cc b/cc/playback/raster_source.cc
index 091c40a2bde84468b0b6430f3c497bd1d9b60248..5c427217041d949a4b150bb4452cc5d03d6ce363 100644
--- a/cc/playback/raster_source.cc
+++ b/cc/playback/raster_source.cc
@@ -69,7 +69,8 @@ RasterSource::RasterSource(const RasterSource* other, bool can_use_lcd_text)
           other->slow_down_raster_scale_factor_for_debug_),
       should_attempt_to_use_distance_field_text_(
           other->should_attempt_to_use_distance_field_text_),
-      image_decode_controller_(other->image_decode_controller_) {
+      image_decode_controller_(other->image_decode_controller_),
+      subpixel_offset_(other->subpixel_offset_) {
   // In certain cases, ThreadTaskRunnerHandle isn't set (Android Webview).
   // Don't register a dump provider in these cases.
   // TODO(ericrk): Get this working in Android Webview. crbug.com/517156
@@ -234,6 +235,8 @@ void RasterSource::RasterCommon(SkCanvas* canvas,
                                 const gfx::Rect& canvas_playback_rect,
                                 float contents_scale) const {
   canvas->translate(-canvas_bitmap_rect.x(), -canvas_bitmap_rect.y());
+  LOG(ERROR) << "subpixel_offset: " << this << ": " << subpixel_offset_.ToString() << ": " << GetSize().ToString();
+  canvas->translate(subpixel_offset_.x(), subpixel_offset_.y());
   gfx::Rect content_rect =
       gfx::ScaleToEnclosingRect(gfx::Rect(size_), contents_scale);
   content_rect.Intersect(canvas_playback_rect);