cc: Stop locking the raster scale factor at 1 after any change.

cc/layers/picture_layer_impl.cc

Index: cc/layers/picture_layer_impl.cc
diff --git a/cc/layers/picture_layer_impl.cc b/cc/layers/picture_layer_impl.cc
index 732b822aa8b78486622b95429e3d29e35c7b14cd..0849c516bab58e63b183c957eb877e748f85187a 100644
--- a/cc/layers/picture_layer_impl.cc
+++ b/cc/layers/picture_layer_impl.cc
@@ -69,7 +69,6 @@ PictureLayerImpl::PictureLayerImpl(
       raster_source_scale_(0.f),
       raster_contents_scale_(0.f),
       low_res_raster_contents_scale_(0.f),
-      raster_source_scale_is_fixed_(false),
       was_screen_space_transform_animating_(false),
       only_used_low_res_last_append_quads_(false),
       is_mask_(is_mask),
@@ -890,10 +889,8 @@ bool PictureLayerImpl::ShouldAdjustRasterScale() const {
   if (raster_device_scale_ != ideal_device_scale_)
     return true;
 
-  // When the source scale changes we want to match it, but not when animating
-  // or when we've fixed the scale in place.
+  // When the source scale changes we want to match it, but not when animating.
   if (!draw_properties().screen_space_transform_is_animating &&
-      !raster_source_scale_is_fixed_ &&
       raster_source_scale_ != ideal_source_scale_)
     return true;
 
@@ -934,33 +931,14 @@ void PictureLayerImpl::AddLowResolutionTilingIfNeeded() {
 }
 
 void PictureLayerImpl::RecalculateRasterScales() {
-  float old_raster_contents_scale = raster_contents_scale_;
-  float old_raster_page_scale = raster_page_scale_;
-  float old_raster_source_scale = raster_source_scale_;
+  const float old_raster_contents_scale = raster_contents_scale_;
+  const float old_raster_page_scale = raster_page_scale_;
 
   raster_device_scale_ = ideal_device_scale_;
   raster_page_scale_ = ideal_page_scale_;
   raster_source_scale_ = ideal_source_scale_;
   raster_contents_scale_ = ideal_contents_scale_;
 
-  // If we're not animating, or leaving an animation, and the
-  // ideal_source_scale_ changes, then things are unpredictable, and we fix
-  // the raster_source_scale_ in place.
-  if (old_raster_source_scale &&
-      !draw_properties().screen_space_transform_is_animating &&
-      !was_screen_space_transform_animating_ &&
-      old_raster_source_scale != ideal_source_scale_)
-    raster_source_scale_is_fixed_ = true;
-
-  // TODO(danakj): Adjust raster source scale closer to ideal source scale at
-  // a throttled rate. Possibly make use of invalidation_.IsEmpty() on pending
-  // tree. This will allow CSS scale changes to get re-rastered at an
-  // appropriate rate. (crbug.com/413636)
-  if (raster_source_scale_is_fixed_) {
-    raster_contents_scale_ /= raster_source_scale_;
-    raster_source_scale_ = 1.f;
-  }
-
   // During pinch we completely ignore the current ideal scale, and just use
   // a multiple of the previous scale.
   bool is_pinching = layer_tree_impl()->PinchGestureActive();
@@ -1129,7 +1107,6 @@ void PictureLayerImpl::ResetRasterScale() {
   raster_source_scale_ = 0.f;
   raster_contents_scale_ = 0.f;
   low_res_raster_contents_scale_ = 0.f;
-  raster_source_scale_is_fixed_ = false;
 }
 
 bool PictureLayerImpl::CanHaveTilings() const {
@@ -1213,6 +1190,7 @@ void PictureLayerImpl::AsValueInto(
     base::trace_event::TracedValue* state) const {
   LayerImpl::AsValueInto(state);
   state->SetDouble("ideal_contents_scale", ideal_contents_scale_);
+  state->SetDouble("raster_contents_scale", raster_contents_scale_);
   state->SetDouble("geometry_contents_scale", MaximumTilingContentsScale());
   state->BeginArray("tilings");
   tilings_->AsValueInto(state);