cc: Remove fixed raster scale, stop rasterizing with will-change.

cc/layers/picture_layer_impl.h

Index: cc/layers/picture_layer_impl.h
diff --git a/cc/layers/picture_layer_impl.h b/cc/layers/picture_layer_impl.h
index 17108518fdfa3eef530a545f4000faa5d9c1fe4f..f9637bf744e8c07e060e069a3f2199d694aae554 100644
--- a/cc/layers/picture_layer_impl.h
+++ b/cc/layers/picture_layer_impl.h
@@ -130,9 +130,6 @@ class CC_EXPORT PictureLayerImpl
   float ideal_device_scale_;
   float ideal_source_scale_;
   float ideal_contents_scale_;
-  // This refers to the ideal scale from the previous frame (or a previous time
-  // the ideal scale was updated).
-  float last_ideal_source_scale_;
 
   float raster_page_scale_;
   float raster_device_scale_;
@@ -140,7 +137,6 @@ class CC_EXPORT PictureLayerImpl
   float raster_contents_scale_;
   float low_res_raster_contents_scale_;
 
-  bool raster_source_scale_is_fixed_;
   bool was_screen_space_transform_animating_;
   bool only_used_low_res_last_append_quads_;
   const bool is_mask_;